I am so sorry.
Ideally I would like to enjoy a polyamorous life with G but I feel we both messed up badly.
I'm not seeing where you messed up. You tried to report your internal weather (feelings) along the way.
If he doesn't hold up his end of the responsibility sticks to you, he doesn't hold them up. His behavior is on him to execute.
Your behavior is on you -- and you choose to stay or not stay with G based on his behaviors toward you.
You may want to enjoy a polyamorous life with G but if his behavior is taking away from the enjoyment part of it? Then what? You break up.
I saw dangers in G's relationship to U. I don't know if I should have kept them to myself,or maybe I should have been clearer.
Sounds like you reported. And when it became a thing, you heard his limit of "let me take care of my other relationship myself" -- and you took heed even though his idea that YOU should roll out the welcome mat more is out of line. (YOU decide how tight you want to be with a metamour or not -- not him. )
Some people just need to learn the hard way. Enter the power of staying silent and giving them the space to figure that out.
When YOU tell him of your need for space and desire to cool it/break up (I'm not sure of degree of separation by your post) he does NOT respect your need though. That's annoying when you acquiesced to his need to continue the U relationship without you commenting on it. Wassup with that?
His need to not be alone trumps your need for a break up? How come his needs are first?
He got hurt and I saw it coming.
But you are not responsible for his feelings.
Nobody can control emotion. It happens when it happens. Rain is rain. Sun is sun. Feelings are feelings. The only thing we can control and change is how we behave. He chose not to change his behavior. Here's a consequence then.
New feelings are going to be felt. Now he can choose his next behavior.
You don't control any of that -- not his feelings nor his behavior.
You can only control your OWN behavior.
By the way I have NOT said "told you so". I feel so sorry for him because she left when he needed her support. I feel sorry for myself as this has been so draining.
Good for you -- not going "I told you so."
Yes, U's timing is unfortunate. It is what it is.
Yes, you can feel sympathy for him on the timing of it.
Yes, do feel sorry for YOU and do your self care -- put your OWN oxygen mask on first.
He is not doing right by you, a significant GF -- in not clearing it up with his kids and letting them treat you like "a cheating woman affair person."
H is no longer around to verify, but this is shoddy that you are not "allowed" to pay your final respects because G will not support your needs at a grieving time.
Yet he seeks you to support his needs? Sheesh.
G desperately needs support and I am giving it but the last years have been such a turmoil that I am emotionally and physically drained. I would say everyone in this story is or was emotionally and physically drained.
You control and choose how you behave.
You can alleviate the volume of your own "emotionally and physically drained" by not giving him any/as much support right now.
Put your energies in supporting yourself. Again, put your own oxygen mask on and do your own self care.
Isn't this the guy you wanted to break up with earlier? Be firm but gentle about your own limits.
"Look, I feel sorry for you, and I feel bad, but I am drained and cannot give any more. I need my own time to process and grieve on my own."
Seek a counselor, a minister, a good friend -- whoever it is you normally seek for comfort at the Big Things like this.
Do the correct thing by H even if nobody else will ever know -- arrange to have flowers placed on her final resting place or go there yourself when the main funeral observances are over, drink a toast to her at her favorite park (or other place), have a private moment of observation, plant something in your yard in remembrance -- however it is you do it.
For yourself -- eat, sleep, perhaps get a massage -- I'm not sure what you like best when you need self care. But do take care of you. It's been a doozy!