In short: No, anal sex is not compulsory between two men.
However, Anal sex is very very nice... and there is no reason two guys shouldn't be able to enjoy it. I don't think I'd be able to be in a relationship, at least not for long, with someone who never wanted to have actual intercourse. To me, the rest, while being quite nice... and often times, more than enough... is simply foreplay. Anal sex, like regular heterosexual intercourse, is simply more intense, and allows for more of an emotional connection than would, say, getting a blow job for instance. Everything is nice, but to me anal sex is the cherry on top(no pun intended). But that's just my opinion.
Anal sex is a scary idea at first... but as long as they know what they are doing, and go slow at first(if you're bottoming), then everything will be fine... and like wise, if you're topping.. just remember to be gentle at first... and also remember, it's forward thrusts, not down.. some guys newer to anal sex have a problem remembering that little bit of info for some reason.
As for unhygienic... a little bit of self cleaning on the bottom's part goes a long way. Also, keep in mind, that given the assumption you have plenty of common sense at your disposal, you'll be using a condom. That's a buffer zone. So as far as all that goes... it's not unhygienic in the slightest.