He lied to and manipulated both of you. You had no idea, and therefore you were not to blame. Both of you were gaslit by the same man.

My guess is that she blamed you because either she really believed that you knew and did it anyway (in which case, she should have blamed both you and her husband not just you) and/or she is so desperate to hold on to her marriage that she has to blame you so that she can continue to feel ok about staying with him (he was an innocent victim, like her, and you were the bad guy)

Whichever it is, don’t take on their toxic baggage and dont blame yourself. Yes, it can be healthy to see if there are things to learn so as not to end up there again (although any of us who are healthy will need to take an emotional risk in order to love), but ultimately you were a victim here, not a perpetrator, and I’m sorry for all you went through- it must have been so painful to discover he was married and lying the whole time and then to be verbally abused by her on top of it.