Good Move, delete h off your f/b. I did, it also saves temptation to snoop.
Shame to hear your MIL is taking sides and not trying to remain neutral, you are the mother of her grandchild if nothing else. Your h will be telling her what he wants her to believe and right now it's what he believes too - try not to take it to heart (which I do know is easier said than done) but down the path a bit they will be very sorry and embarrassed people. Don't communicate with her unless absolutely necessary, I did not talk to mine for months because of the rubbish she told people, my FIL started emailing me privately to give me the heads up to what expect next from her so I was prepared.
As for the strip clubs and all, he is acting out and trying to portray to the world he has it all now he is free and single, but to many and those who count all they will see is a sad deluded man who just left his family for no good reason.
Let's get the focus off him and his family and back on to YOU as you are the important one here. Getting you to start moving forwards with your own life and find your inner and outer smile again.