Welcome to our forum.
has a good site you can direct the guys to, the FAQ page
in particular. This is partly up to the guys, as they must be willing to take a closer look at their feelings and see if they can tell what they're really worried about. If they're determined to stay mad at each other, it's not like you can make them do the homework.
Polyamory is certainly a viable option as long as everyone involved agrees to it and works on communication, etc.
I hope this site will be of some help to you.