I don't blame you a bit for your choices on this. I haven't followed your sitch too close, but I do know you have been at this for a very long time. The good part is, this long journey has given you / me great insight and the experience, although terrible, is a blessing in disguise.
Looking back, would we do things different? You bet! But.... looking back is just that, looking. It is how we received the future and it's challanges we are now better prepared for that will define our place. I've been right where you are, on the right track, but realizing our spouses haven't the character to to bring themselves back to the relationship, even as they see the hurt and dispair this has caused. I have come to a point where I have very little respect for my XW. It is respect that will have to be earned to restore, I just can't ever see it happening. I also see how carrying this is a burden and with time will work through the issue. You have reached a point where you know you have had enough. Critical boundaries have been breached and the emotional scars are deep.
As you have posted, take this time to let Nicola shine, get comfortable with the new environment and bless those you touch with your character.
Keep smiling, keep singing and follow the path you are on. It is your path, being traveled one step at a time. Travel it with the dignity, honor and character you display. With the efforts you have put forth, you will be rewarded tenfold.