well, at my house, after 10 years of being together and less than that for being maried, she calls ALL the shots where sex is concerned. I never have any say as to when, what kind, how long, nothing. That makes it really hard to find that part of the relationship.... ummm, fulfilling. It's good, but it could be SO much better. Somehow imo you need to find a way to keep it like it was in the beginning. Of course, age, kids, work, etc., that does play a part about how things evolve. It makes it so much easier if each partner isn't selfish. My motto is "you have to give to recieve", that certainly isn't a problem on my part, I enjoy giving almost as much as getting. Not so with my wife.
Also, as MM said, you can't paint women with a wide brush, my wife's idea of forplay is "I'm horney, get naked." That's it. I like the more extended version. Now, if I feel like giving a full body massage, I'd prolly have sex more often, but who feels like doing that every night, or for that matter, every week just to have sex, not me. Sometimes, sure. And do you think that I have ever had one, guess no and you'll be right.
I have an explanation that i often tell my wife, of course it falls on deaf ears, but maybe someone else can use it in their relationship to make it better.
There's 3 kinds of sex:
1) fast food- just all the sudden getting the urge and getting off whenever, where ever, takes 5-10 minutes. Both smile at each other and say "whewwww".
2) regular meal- geting to bed, have time to relax, shower, enjoy some cuddeling, pillow talk, have sex for as long as time warrents, go to sleep in each others arms (probably happens during the week)
and
3) gormet sex- send flowers during the week, make plans for the weekend, leave sexy notes/emails, plan a weekend together (maybe at a hotel) bring toys, other aids, spend the night massaging, trying new things, using the toys that you don't normally have time for, probably stay up half the night.
IMO, it takes ALL 3 of these to have a great sexlife. Number 1 is JUST as important as number 3. If you can find a mate that understands this, your a lucky person.