Freaking out!

I am 36 years old. I have had fertility problems for 10+ years. My husband and I are getting a divorce. He is unfortunately struggling with drug addiction. The divorce will be final in May (hopefully). I have slept with one other person. But I also slept with my husband around that time too. So I do not know whose baby this is!!!! How is this even my life. Years ago I wanted another baby but now with everything going on in my life and my age this is not a great time. I do not know what to do.