2 for me. The second is really reluctant to tell me his number, but I know it's more than 30 and fewer than 100. I'm curious only in a cursory way, because my ex almost never talked to me about sex, and I think it's good for my writing. I'm 27.
And I do think there's a number that's too high, but I think it's different for everyone. I think you've had too many partners when sex becomes a mechanical chore that you do because you don't know what else to do - which is probably the point that it's a sex addiction. That number can be very low or very high, but I think when someone crosses that personal line, it's too many.