Cuddling post-sex should be reserved only for someone you actually have a commitment with, not for hookups. Most people just want to enjoy the last strains of ecstasy in silence; some would even turn their backs on you afterwards. If you really want to at least talk to this person for a good few minutes, then steer the conversation away from personal stuff. Smoke, browse through Facebook, check Twitter, or do other things to pass the time, then get up, take a shower, and leave. Give them a peck on the cheek before you disappear, though.
Some relationship experts counsel never dating while separated but not divorced. What are you both hoping for from the separation? Coming out of a marriage is emotionally taxing. Spend some time with yourself first. You need some time and space to fall in love with yourself again first and foremost.