Bea, I still think that this meeting should be between the two of them. They are both adults and they will have to learn how to mend the bridges on their own. If your son was a teenager or younger, I would say yes, go in a heartbeat, but your son is older and should be able to meet w/his father and if need be, lay it all out for his father as to how he feels w/o his mother being there as a buffer or anything else.
If you opt to go, then I would do as Wonka has suggested. Go, say your hellos and then leave after a bit. It's time that your xh figure out how to communicate and mend the bridges w/his sons. After all, he's the one that burned the bridges and he's got to be the one to rebuild them. You can't go around rescuing him from his bloody mistakes or he'll never learn how to communicate w/his sons.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
