I would tell the OMW if her H has any conversation with your wife... do NOT keep that info to yourself.
And yes I would go to his home with his WIFE present (I would never confront him in private... NEVER do that.. he could tell someone you hit him and NO JUDGE will believe that YOU didn't touch him right now)...
With his wife there, warn him AGAIN. Tell him you KNOW conversations took place..
There are some other good things if you noticed :
1. Your wife watched TV with you 2. Your wife SPOKE to you during the program 3. your wife wanted to see your phone
on 3, its interesting, I don't konw if she wants to see if you called OM, OMW, or if she wants to just see who you talked to that day...
But you played it perfectly... just let her look at it if she picks it up...
NEVER hand it to her without her asking for it... if you do THAT , she will assume you cleaned it up first and are trying to trick her.. wait for her to ASK for it or for her to just pick it up... do NOT get defensive about your phone at all. You did well.. keep that OM out of yoru wife's life though... he's NOT listening to you clearly.
Telll him if your wife approaches him that you want him to WALK AWAY... NOT say a WORD...
I don't know the law that well, but maybe there's something legal you can do to keep him away?
Can you at least run a background check on this creep?