A man discovering that his beloved girl is a virgin is like a man living in his dream house discovering a hidden treasure in it, it's a overkill of happiness...
Even if it was a lie, I'm sure most guys would feel a bit depressed hearing that their girlfriend has seen...countless dicks before.
I can't really understand why girls would think guys wouldn't like a virgin...If anything, it makes it all the better, much more of a 'reward', as our protagonist puts it! Age doesn't change that...