Re: what do you think?
You say the other man's marriage broke down. Does this mean he and his wife are now divorced? If they are still married, you may want to speak with the wife--see if she can be of help. Also, tell his family and your wife's family what is going on. This relationship should be exposed.
You should move back into your marital home. Don't make life easy for a cheater. Since your wife is the unhappy one and wants to toss her family, then she needs to be the one to leave the family home. You need to be there. Your children need stability!