Sex with my exs friend

My ex of one year who is currently serving time has a friend that over time grew close to me as well. In this two years we've become great friends and we are there for each other with anything, rather is a popped tire or dog sitting. My ex and I will have no possible chance of getting back together once he's out that I know of because I am so done with the "

Bad boy" stage. This guy though, I know it can never be anything with him and it'd simply be a friends with benefit type of thing but I'm taking a lot of things into consideration such as his and my exs relationship when he gets released. Mind you his friend has a daughter (no wife or girl friend, just daughter) an I feel guilty towards the child for sleeping with her dad. I feel as though I'm coming between her potential family. At the same time though, I want to be an adult about it, I have needs as any guy has needs and he doesn't "pillow talk" and I know I'd be able to trust him. Would you or would you not sleep with him ? He says we should I say I want to but we shouldn't. Mind you I lost my virginity only 6 months ago and after, my boyfriend d broke up with me and he will be my second partner.