I know he loves them but I also would like him to know the realities of being the person who is there 100% of the time instead of the person who visits.
It is a difficult balance. Clearly he cannot continue to drop by and visit whenever it suits him and then go and hide at his place when it all gets too much. And he cannot expect you to carry the burden of the family 100% of the time. I suspect he will respond, it will take some time, because he will want to think his words through carefully, but he will respond.
Perhaps validate "I can see how you feel that way ..." and then state an alternative "I know that we are both committed to the children and want whats best for them. Having the kids full time doesn't work for me. How about we agree a schedule where you have them one night a week and every second weekend. I will stay at my sisters".
From what you describe, I think his MLC fog is slowly lifting. He sounds like a rational man (not a common MLC trait) and he is trying to be considerate of how things impact you. He fails sometimes (inviting you on the boat and then not out for the rest of the day).
When H was at his worst, the last thing he thought about was the impact of his actions on me. He told me he thought we were finished on my b-day last year, saw me breakdown, and then thought it was still ok to go Dubai 2 days later to spend 5 days with a school friend who had just got divorced. He literally did not speak to me (unless you count huffs and growling) between christmas and NY. 2 days before NYE he announced he had booked to go to a NYE party with another friend (also divorced) and his GF. He didn't seem to care that I was a shattered mess by that point. He even blamed me "you never want to go out NYE. I always end up sitting on the sofa on my own" (woes is me, we have young children you [censored]'.
Compare that to last night when he asked me if I wanted to keep our dog home with me instead of going to his flat with the girls 'so she can keep company'. Ditto the anger and the cherry picking bad moments in our history and focusing only on those. I think your H is further on the awakening path. They do say that sometimes, even when the LBS is still standing, even where the WAS want to come back, the guilt over the hurt they've caused and the huge uphill battle to R is too much for them.
What I'm trying to say is tread carefully. He is further on his journey then my H (who still wants to check if the grass is greener), but your H knows he [censored] up and he is trying to make things right (note: i did not say trying to R).
You and I, and others here have set ourselves on a long and painful journey with no guarantees. I am glad you are here to hold my hand (so to speak) whilst I walk it.
Have a great time with your sister. Against DB'g but I would text H a happy birthday.
