Honestly, use your head. Don't ask, don't tell. Don't ask if she has a boyfriend and don't tell her if you have a girlfriend. But make damn sure you have condoms! You don't want any curtain climbers coming around in 9 months....
The girl is not married to anybody. Her boyfriend doesn't own her, and he doesn't even attend the same college. This whole situation could be solved with a phone call--" Hello, Honey? I think it's best we see other people. You'll always be special to me, but right now I've got to go knock the socks off a virgin. Keep in touch, 'kay? Bye!" If the absent boyfriend wants exclusive rights to this girl, he can a.) change universities, and b.) put a wedding ring on her finger. Otherwise, it's "All's fair in love and war." He's probably dating other girls on the side anyway, if he's anything like 99% of the men I know. OP needs to step up. If he's saving his virginity for marriage, well good for him, but he should be fishing down at the Christian Life Fellowship pond instead of the deep blue sea. If he's ready to take the plunge, he should just do it already. Everybody was a virgin once. As a high-school sophomore, I lost mine at a kegger to a junior girl that I barely knew, and I was glad of it. But I suppose other people may feel differently about that. My advice: use a pre-lubricated high-quality latex condom, and call her the next morning and ask her out to dinner. Oh, and no fair kissin' and tellin'. If she's willing to sleep with you, at least have the good grace to keep it to yourself.
If youre intention is sex, then just nail her and be done with it. Dont invest feelings though, as long as the guy is in the picture. Dont make it any more complicated than it needs to be. And all the other information clutter, it makes no difference!