I would wait and see what the surprise is. If it's a visit, he stays in a hotel and not in your safe haven space. You are under no obligation to share your life w/him...only share what is necessary where the girls are concerned. They can tell him about what they are doing now since they are older and wiser.
Set your boundaries and stick to them. You know the drill...they come close when they are at loose ends when they split from the OW and if the OW contacts them...off they go again. I do not want to see you hurt/disappointed and keep those expectations at zero and look to him as a long lost cousin.
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.
