hard to define...
I'm generally the faithful type, and I had a girlfirend I loved quite much (and I still do), and she did love me too (but she doesn't anymore) and our sex life was pretty... not regular, but frequent, even if little ...mundane (because she quickly got used to my dominancy caused primarily by how attractive she's to me so I couldn't really restrain myself, so she became pretty passive)... but she broke up with me a while ago, saying she still cares about me a lot, but being in a relationship with me hurts her (makes sense, kind of), but sex with me was good (no wonder, I'd like it too, being in her place), and she's no type for one night stands or making new relationships quickly, so we kind of agreed we'll be friends and have sex, BUT...
...lately she has virtually no time at all, expects something different than me (her: imagine something porn-like; me: imagine something including feelings too, as I still love her), so it's kind of strange... despite that, I don't want, can't imagine, and even if I wanted and could imagine have no opportunity to, have sex with someone else...
so suddenly it's kind of infrequent (VERY MUCH infrequent, even for her standards, as I know them) and strange... to put it short and in facebook terms: It's complicated... :/