It sounds like there really is no advice needed on this one because you have already made the decision that you wanted to make. You went back to your ex and are pregnant with his child even though you didn't want to be in the relationship in the first place. I would honestly advise against going back to your ex since you weren't happy before but you are going to do what you are going to do no matter what anyone online tells you. I think you know that what you are doing is wrong, technically, so if you plan on raising your ex husband's child with him as the father then you need to tell your current husband what is going on. Good luck with dealing with your ex's family because they definitely won't approve of this situation, I am almost certain of that one.