Trouble in paradise

So recently I found out that my bf for over a year was married to his ex who he shares a kid with. They are both military and got married overseas so that they could relocate to the same place for their child. By no means am I upset about the fact that he was married to benefit his kid, I’m upset that he didn’t tell me from the beginning. He repeatedly has told me that it meant nothing, they didn’t bring it back to the states, never lived together, etc but I still felt weird. He told me they tried to get it annulled but could not. Months after me finding this out he decides to finally open up to me about it all. He said a lot of the same things but now revealed he is not divorced yet just legally separated. He said that they have done all the paperwork and paid all the fees to be divorced they were just ordered to do a parenting class which they have not done yet. He said they have been legally separated for a while now and both have dated others and want nothing to do with each other. But This all threw me for a loop because I don’t know how to feel dating someone who is technically still married... or what that means for my relationship. I do love him and believe he is in love with me but I just feel kind of lost. Any advice is helpful, feeling really low right now.