My boyfriend were having sex and we stopped for a second and he felt to make sure the condom was still on and it was. We kept going and just a minute later I was hurting so we stopped and he checked and the condom had came off and it ended up on the bed. We got a new condom and continued and after he finished he checked to make sure it wasn't leaking and it wasn't. How likely is it that I can get pregnant from a few strokes without the condom?