Is it worth my time and effort

I started having a friend's with benefits ordeal. It has slowly developed into a few times a week and various times of day not always being a sexual encounter. xtended period of time. We started as a once in awhile get together. Now we see each other several times during the week, I have met his child, and I have no clue as to how he feels towards me. Are we going to pursue this or am I just setting myself up for a fall when his girlfriend gets out of jail.

You are his 'in-between' girlfriend to tide him over, and as soon as his real girlfriend gets out, he will be finished with you. He thinks you understand that. He believes you are only in it for the sex, like him. Get out now.