Confused and sad

So, I’m going to see the therapist by myself today.
I was very upset last night, so it’s probably a good thing.

It is difficult with today being the anniversary of our wedding 14 years ago and vow renewal 3 years ago.
Only 3 years ago she loved me enough to renew her vows.
Now she tells me she won’t move back unless I let her keep her married boyfriend on the side.

Did I make mistakes as a husband? Yes. I did.

But, what did I do that was so wrong for her to bring another man home only 893 days after vowing to love, honor and be faithful to me?

And, if what I did warranted that, how could she be willing to come back?

I can’t make sense of that.
Maybe the therapist can.