Last American Virgin was director Boaz Davidson's remake of his own Eskimo Limon (aka Lemon Popsicle), a popular Israeli film which spawned 7 (!) sequels.
Last American Virgin is a bit of an oddity, it's a wacky comedy for the entire duration - complete with a fat kid boinking a middle aged hispanic prostitute while a comical song plays on the soundtrack - then in the last few minutes they hit our main character with a devastating emotional groin punch. And then... it just ends, no glimmer of hope for this guy or anything. Sure, it's a more realistic ending - sometimes in life, you're just gonna get screwed and there will be nothing you can do but stand there and take it. I admire the balls it took to end it like that. But, really, who watches a goofy comedy with fat kids nailing middle aged hispanic prostitutes and thinks "man, I hope I'm really bummed out and sad during the last couple of minutes of this thing."?
You want the main guy to start off cool and likable, turn into a jerk going for the hot, but incompatible friend of his equally hot, but more down to earth friend. Then you have him realize he's a jerk, redeem himself, end up with his equally hot, but more down to earth friend. Sorry, I've got Secret Admirer on my mind for some reason. Still, that's the basic formula, it's worked a thousand times without bumming everybody out.
That said, bummer ending or not, American Virgin is a pretty solid movie that I recommend checking out at least once