My advice would be to hold off on signing anything.
It's only been 3 months? My H called me 3 times the day after he moved in with OW and asked if I had talked to my attorney yet. I held off, but eventually saw my attorney to find out my options. I got all of the paperwork together to get child support started and gave it to H. He never got any of the information back to me.
Upon advice from my attorney, because of circumstances in my life, health, etc., separation was recommended, not a divorce. When I told my H, he had a fit! He bitched and moaned and called me every name in the book. Then he threatened to get his own damn attorney and get things rolling. I told him to go ahead, but I wasn't feeling compelled to sign any type of papers at all...divorce or separation.
I felt empowered because I put the ball in his court, and instead of playing, he took his ball and went home. (Granted, he went home to the OW) He is back now, and things aren't peachy, but I am working on it, despite the OW.
Stand your ground and hold off until your emotions are under control a bit more.
