Mel, your h sounds like he is still very confused and is trying to figure out which way to go. It sort of looks like he wants to keep you on the hook for now because he isn't quite sure what he wants to do. He needs that anchor.
I don't know if your insistence that he end the A or leave in June is an ultimatum or not (sounds like it to me) but I do know that you have to be willing to follow through with whatever consequences you say will happen if he doesn't end it (he moves out). Otherwise, you lose your credibility with him. Just like with a child.
You also have to consider that he will just lie to you about it if it continues. From all I've read on here, you have to let that affair die a natural death.
Regardless of all that, I'm sending virtual hugs your way.
By the way, my h frequently asked to join in on "my" vacations and we seemed to have a great time. But once we got back to the normal routine of life, all the MLC stuff came right back. I avoid vacationing with him now.
Me: 59 and holding H: :53 Me: 1 S, 1 D, both grown M: 19 T: 23 BD: 9-23-2013