Yes, back off. Sadly I had to go through the same thing. OW kicked my H out and he spent a good 3 months on my couch texting/sending you tube links/etc about how much he loves/misses her and how lonely he is without her.

Fast forward 2 months and he says he has no feelings for her anymore.

Me: 35 husband:39
Sons 16 and 11 from my first marriage
Twins 5 (boy/girl)
Daughter 3
Affair bomb 2/27/14
He moved in with ow 3/13/14
OW kicked him out 6/15/14
4/2016 he seeks help for sexual addiction