Here’s the deal with guys and condoms, as far as I’m concerned:
If he has an issue with the condom itself, investigate other birth control methods and/or ways to prevent STD transmission (ie the birth control pill/patch, IUD, nuvaring, diaphragms, spermicide, etc. for birth control, DEFINITELY getting tested for STD/STIs). If he refuses considering these options, that’s when I’d be worried about him being manipulative and not upfront about his investment in the sex itself.
Condoms can, indeed, be an issue for some guys. Sometimes it is a problem with the size, as many people are alluding to above, for which you can find larger sized condoms. Sometimes it is a problem with the amount of stimulation involved, that the condom cuts down on the sensation. Ways to get around these problems can be trying different types of condoms (extra sensitive, extra thin, etc.) or trying other birth control methods (assuming STDs aren’t an issue). It may have to do with a mental issue surrounding the use of a condom itself, which he’d just have to deal with as it came up.
I never trust any guy who doesn’t want to consider using a condom. More than once, I’ve been in a situation in which the guy I’ve been with doesn’t want to wear a condom, and asks if I’m on birth control, assuming that the fact that I am will negate the need for a condom. NOT TRUE AT ALL. I insist on using one, regardless of the fact that I’m on the pill. Good thing too, because I had someone accuse me of passing an STI, which I didn’t (for the record – I’m VERY CLEAN, thank you VERY MUCH), and I knew it wasn’t possible because I had insisted on the use of a condom. Any guy who refuses to protect himself with one partner probably hasn’t taken much time to protect himself with others, and if he doesn’t respect her enough to care about her health, safety, and the prevention of pregnancy, then she certainly shouldn’t be having sex with him in the first place.