I have been on both sides of this... heterosexually married (with kids) and in a monogamous gay relationship of long duration.
My experience agrees with -L-'s as far as the hetsex part goes. It was workable; we had kids; it didn't gross anyone out; it wasn't a caricature of intimacy; sometimes it was even tender.
When I first had homosex, it was like being transported to another plane of existence. The synapses in my brain went into overdrive. It was electric. The experience was unbelievably potent. I cried afterwards from happiness. It was truly making love for the first time.
When people ask me how old I was when I first had sex, I always use the age of my first homosex. Then I tell them that prior to losing my virginity I was married and had several kids. :-)
I still remember that first sexual experience. (Insert cinematic dissolve here)
Since this is a PG-rated blog, you may have to use your imagination here. But I'm not kidding: having the kind of sex you're wired for is a completely different experience from the other kind of sex.