Lea, you sound surprised by your MIL's response? Don't be. In the end regardless of how great a relationship you had with her, she is your husband's mother and if he jumps off a cliff, she will support him in this.
You also may be late to this party as well. You don't know for certain that your H didn't already speak to his mother. Maybe told her a bunch of bad things about you, how he couldn't live in that environment anymore and that he really wanted to be happy and that maybe meant pursuing a relationship with another woman. Seriously it's not that far fetched to consider this.
You got the response from your MIL 'It is not for me to judge why H left.'
If your husband had spoken to his mother and told him you had cheated and had an affair, your MIL would take a strip out of you, I can guarantee that.
It may be unfair but it is reality and you know my take on that, observe reality, follow reality, don't reject reality, just go with it.
If you were expecting your MIL to tear into your hubby, that was the wrong assumption, it will never happen, she just wants her son to be happy, with or without you. She would never put you in front of him, it rarely ever works like that.
So back to reality... No one will tell him what your husband's done is wrong because it doesn't matter who is wrong or right, it won't change the situation, you can't guilt him into coming back, that never works.. As far as his share of the drama, let go of the need for him to experience anything bad. Yes he got away with it.
As for OW's husband, are they still married, separated? Do you know. Are you sure he rec'd your communication on this? Again if he doesn't care, nothing much you can do at this point.
What's your plan right now given the current situation?
Sitting around, twiddling thumbs and hoping someone to give your husband a reprimand for his actions didn't work out. What's next?
