Splitting the costs when living together and one person has an adult child.

In my opinion, 3 adults = rent split 3 ways.

if you split 3 ways do you not take into consideration the difference in incomes?

You have to decide what is more important to you – your relationship with her or the potential financial inequity. Is she aware that her child is a problem? Is his not working a source of anxiety for her? If it is, I would not add pressure to her by bringing up the money. You might want to talk to her about the problems her son causes for you in the household or the relationship but I would keep money out of it for now.

Totally objective standpoint:

Base the split on the percentage of household income of each person. Assume that the non-working adult can at least pull minimum wage, and go from there. Since the child is not yours and thus not your responsibility, she can be responsible for maintaining his percentage of the household payments.

This is a simple one for me, because I wouldn’t have a relationship with a person who brought a non-contributing adult child into the relationship. It just wouldn’t be part of my calculus, except on a very temporary or emergency basis, and even then the person would be expected (by his mother, in the relationship that I would have) to “participate” in some way, even if it was at a minimal or even strictly social way. Just “being around, and being pleasant and generally agreeable” (as you might expect of any guest, for example) could be enough.

So you need to have the conversation with your SO, and stick to “how I feel”. “I feel taken advantage of,” for example, if that applies, or even “I feel taken for granted”. Consider that your negative feelings – however honest and right they are for you to express – may spell the beginning of the end for her. If she thinks that it’s okay for kids to mooch off their parents indefinitely and you don’t (nor do I, by the way), then that may become an insurmountable hurdle.

Most people I know split it percentage wise. So the higher earner pays a higher portion. I think the son definitely needs to contribute if he is an adult. Contrary to what @CWOTUS wrote, I do think it is good sense to consider what a person has or does not have before entering a sexual or romantic relationship with them. Or step back. Since doing it after the fact seems wrong somehow.

I don’t think that was contrary to what I wrote, @Shippy; it was pretty much the point of what I was saying. That stuff has to be considered and sometimes the relationship not even begun if the other party has such a diametrically opposed viewpoint about the validity of non-contributing adults in the house.

I wanted to add a belated “Welcome to Fluther.”

The problem I have with the now adult child is that we have known each other since he was in school and I have always said he should have at least a part time job and still be contributing around the house with chores and whatnot. I have always made this clear but it has not been taken seriously and now it is a problem for me. How do I correct this or is it me that has to change the way I think?
I believe everyone should contribute to the household from an early age and as they get older they take on more responsibility, which gets them ready to be on their own.

@CWOTUS has it right in my opinion. This isn’t something that can be objectively determined with some consensus from the general population. This is an issue that goes to the core of the relationship, and will be the basis for money matters going forward as long as the two of you are together.

Each of you has to feel the agreement is fair, because otherwise one of you will always resent it. It is between you and the SO (the grown up child has no say in the matter unless and until he is putting in money, and then it is by full agreement by all sides).

Good luck!

@CWOTUS ah! apologies.

You have to consider how much you are willing to give to maintain a relationship with her. You can see a future where you are supporting this adult child in your old age. Is that OK with you?

I think if it’s not that you should consider breaking up with her. She is not going to change how she interacts with her child.

Fair would be to split the costs proportionally based on your take-home-pay, including the offspring.
On the other hand @marinelife has some good points to consider because that’s the reality, and it does not sound like the kid will contribute much.
If your partner makes a point of frequently expressing gratitude for your generosity that can go a long way toward making it seem worthwhile. Otherwise you may simply be her (and the kid’s) meal ticket.

Is he in college ??? If not make him get a job and help

To me, it’s how badly do you want the relationship? Do you want to be with a woman that lets her son mooch off her and you therefore are partially responsible for his upkeep? If that’s not ok, then you have to set some firm boundaries, goals, deadlines and prepare yourself for the possibility of nothing happening. If nothing happens, what are you willing to do? Move out? Kick her out? Who’s on the lease?

To me, income disparity makes no difference. Everyone should chip in with some form of payment, either monetarily or with work.

Does this adult child have a diagnosed mental illness?

What kind of mother is she that she allows this to happen? Is that the kind of woman you want to have a relationship with?

Fair, in my mind, is to split it three ways but proportional to each person’s income. If the adult child doesn’t work, he should be contributing in some other major way. House/lawn work, cooking, etc.

I would simply do an equal three-way split, I don’t consider that at all unfair.

Is it the money split which is bothering you or is it the fact that she chooses to enable an (apparently) able bodied adult and (apparently) ungrateful and unsociable child of hers to continue to take up space in your home?

EVEN IF she were quite agreeable to pay ⅔ (for her and her son) even if more of a financial hardship for her than you, would you be any happier with the situation than you are now?

My hunch is the answer would be NO.

The real problem youre dealing with is the attitude and lack of motivation of the son as well as her apparent willingness to allow this to continue.

The finances are merely the starting point for the conversation. Before you have that conversation, you need to make a personal decision as to where to draw your line in the sand and what the consequences will be if and when that line is crossed.

How much longer are you willing to have this jobless non contributing sponge in your living space?

You can’t set a deadline for him. That’s her job. You need to decide what deadline to set with her.

Suppose he does get a job and still continues to live with you ? Is any amount of money he makes going to compensate enough for his unpleasant personality?

These are issues only you can answer. But you need to have the answers for yourself before tackling the conversation with her or it could simply end in a muddled resentful mess.

Decide what you want and then ask for that clearly, without ambiguity and set a date with consequences. And then stick to it.

One of the many problems of living in an uncommitted relationship. I made that mistake and will never do it again. It sounds like you are going through an awful lot of negativity for a woman you do not love enough to marry. For an adult child there are more things to consider than income levels. The equal split should include the ability to treat their room as their apartment with overnight guests. Are you ready to live with the revolving door of strange that he will be bringing into your home? The thievery that will happen? Are you prepared to live in a commune with you as the benefactor? Having some experience with young adult sponges, I can only suggest that you come up with a deadline that either the child or you move out. A mother who allows this type of disrespect to you will never change and a young adult with no passion to become their own person will only bleed you dry. She obviously did a horrible job as a mother in not teaching her child to be self sufficient. It doesn’t have to happen right away but a quick deadline for him to have a job and pay you a set amount that you will hold for him to have startup apartment money/deposits/etc. You absolutely have to set your own deadline for how long you want to continue to live in a negative environment when you can be living a happy life. I can only say that if you want to shack up, be prepared to be taken advantage of. Oh and one last thing, be aware that changes forced on a woman who does not feel obligated to do her part to make a happy home, will be seriously be thinking about riding the child support train so you will have to continue to support her for another 18 years. be careful…

I would split the bills however you would if there weren’t a teenage son living there and then charge her extra for whatever extra expenses there are because of her son. For example, if you have to get an extra bedroom for her son, then she should pay for the cost of the extra bedroom. I wouldn’t be too petty, but I think she should be accountable for her son, especially since it doesn’t seem like you have a father-son relationship.

I would be very uncomfortable with someone who allowed her grown child to live with her and didn’t require him to have a job or be accountable for himself. I think there will only be disappointment and resentment with that relationship. I would guess that the next chapter will be you and your GF helping to raise his children for him. If he’s not responsible for himself, he won’t be responsible for his children, either.

Why doesn’t he work and why is he living with you? Why is it ok for him not to contribute and why does his mother enable this?? Lots of why?