this is another serious question: how long after a break-up is it considered acceptable to turn down sex on the basis of preferring friendship?

because we were around two and a half years since the breakup, and it had been something like a year since we'd last had sex (she was actually pregnant for the bulk of the second year). the last couple of times we hung out, it hadn't come up. in hindsight, i guess they were more normal types of dates - coffee meetings, walks by the water - but i didn't really feel that way, i just felt like i was hanging out with a friend and connecting. & there was the awkward dinner with her family like two years after we broke up, when her older sister actually seemed to think we were back together. maybe it was closer to happening in her mind than in mine.

it was just wrong, to me. i preferred her as a friend, at that point, and didn't want to muddy things. but, she was clearly shocked and things were never quite the same.

am i not right on this, though? isn't two and a half years enough time to acceptably refuse sex without it damaging a friendship?