err ... there are so many possibilities on what could had happened and what you can do now that you've called the bugger ...
Prepare your "personal things" in case it escalates to "out of control" & eventual divorce/separation. So depending on whether you want to continue the marriage and how much you "love" your wife or if vice versa ... you'll have to open things up and trash with her ... what's been lacking or if she's unhappy or what not ...
OR else you sit inside your little cave & be cuck00ed and be miserable and "eat out" & be quiet ... for the "sake of your daughter". I've heard of a family like that where the parents sleep in separate rooms (due to father's wayward ways) & eventually child thinks it's "NORMAL" for that arrangement. kid ends up confused & probably straightening out things would be better for the kid.
Next time talk to him ... confront him ... you are her husband ... you can tell him to F^&* OFF and leave your wife alone? Like some of the bros say ... you fight for your wife ... if she doesn't appreciate & reciprocate , then it's okie to let go.
But b4 that ... try your fullest to be calm and collected when you discuss this with your wife ... take her out or something and try to make it as non-confrontational as possible ... ask nicely & state your ground rules ... what you "suspect" & you are willing to let it go (erm ... let's say you still want to save this marriage) if it stops now if she gives you some explanation ... ask her what you can do to help or change or do ...
alternatively ... you ignore / eat humble pie and start eating out
If you're happy with that ...