okay i feel for you on this one because ive been there. my girl and i started off using just condoms then moved on to both now we just use the pill.
condoms are nice to use with birth control because neither one is full proof. there is always that 1 or 2% chance that something could happen. and yea i understand the whole "cumming on her" thing. thats a lot of fun for us too ;) but if thats the deal, have him take it off right before he does.. thats what i used to do. it only takes about a second or 2 to pull it off after he pulls out. so if its that big of an issue and you really want him to start wearing one, but you dont wanna lose out, give that a shot.
the only reason my girl and i stopped using condoms was because we stopped using them for a while, then when we went to again, they were too small for me.
and also, i would like to say that i am happy that you both are faithful and you dont have to worry about STDs, cause faithfulness is awesome and you never know whos got what nowadays