Cheating fiance

If you don't trust him, why are you still engaged?

I just found out two days ago. I have givin him his ring back. We have two kids together so I'm not sure what I should do

Oh, man, I'm sorry you're going through this.

Like it or not, because of the presence of your children, he is in your life permanently. You might want to work with a lawyer or a mediator to assure support for your children and to work out equitable visitation, etc. I realize you may not be zooming ahead in your thoughts about this, but it's something that will need to be worked out eventually.

I just went to a mediator today. He says he wants to go to councilling and work through it. I'm not sure if I'm rushing it or if I'm making the right decision.