Well, I know for sure what doesn't work for me. For my ex, twice a week was pushing it and he wasn't really big on foreplay, so even that didn't last very long. I actually learned a lot about myself, my body, my erogenous zones AFTER we broke up. It started with the spontaneous orgasm I had reading the erotic Sleeping Beauty book by Anne Rice aka A.N. Roquelare (discussed in an earlier thread) and led me to some serious self-exploration. I am single now, and I love both my Rabbit vibrator and my shower massager - and try to spend some quality time with each several hours a week.

BTW, my ex and I broke up for other reasons, but I for sure believe that sexual compatibility both impacts and reflects other aspects of the relationship.