What can I do about him?

Forget him. It’s very possible that you only “want” that other person simply because you can’t have him.

Get the engaged party out of your sight, your head.

I am with @Val123, forget him. You should also take a break from your current relationship. Even though you say this person is special to you, obviously they are not special enough to let yourself fall emotionally involved with some else. Even though you may not be seeing this other person, you are still cheating on the one you are with.

Flip a coin? I’m sure you already know the answer.

Do about what? Nothing you can do about the engagement of another.

Break up with the poor dope and give him a chance to find someone who will really love him. Leave the other guy alone, he’s engaged.

I doubt he’s that close to your heart if you want to fuck this other guy so bad.
You know what you want. Be fair to your man and cut him loose if you’re going to stray.

Seriously, I think we need relationship classes in school.

I’m going to be blunt:
If you cheat on your current beau with a married man, you’re being a terrible human being.

I think part of the allure is the fact that he’s unavailable. If you got him to ditch his gal, then you’d know that his character isn’t as pure as you’d like to think he is, which would make him less attractive to you once you had him on your hook.

It’s the way these things go.

Look elsewhere dear, and save everyone a lot of heart ache.

How does he feel about you? is he willing to leave his fiance for you?

@slick44 Come on! Talk about totally screwing up other people’s lives for a whim! Don’t even encourage that shit.

Dear,
Some things in life have greater magnitude than the litlle things we sometimes “want” or “desire”, just for fun, just because we think it will make us feel a certain way, for a certain amout of time.
When you say you “want” that guy, I understand that you desire to be with him, not that you feel he could be the lost love of your life. If I am correct, the only thing you should do, is respect another person’s choice for life and not ruin it for a short term whim.

…RElax it was just a question, i would have told her it was a bad idea, but she didnt answer. Take a chill pill

I think the OP already knew the answer to this question before it was posted.

He’s not available; do nothing.