I agree with SN: me too, the less I have sex, the harder it is to have sex again. It becomes almost a chore, there is much more pressure, etc. If I do have sex, I'm more likely to have it again. Then again, it's not a sure thing either.
I don't need sex to feel love, but I do think it's a different kind of love without the sex. I don't think it's friendship though, I still think it's love.
I also don't see sex as something that's independent on other people. I mean, if I'm missing sex with one person, I'd never go get it with someone else, because they're just different things. And similarly, having lots of sex with one person won't mean I'll "need" it less from someone else. I don't have a "sex" gauge that can be filled up by anyone. It's more of an intimacy thing that's dependent on each person, depending on how close I feel to them, how much I trust them and how attracted I am to them. However I can feel close to someone emotionally and not physically, or have a phase of not desiring intimacy with a specific person (or altogether).