hmm.. I think it's best not to go overboard with the "love her endlessly"...(sounds too romantic to me) but DO tell her happiness means very much to you.
I'd bring up the elephant in the room (explaining why on earth YOU stayed in this terribly lonely m so long and how you have not been your authentic self, etc) with a comment that
You assumed that remaining in the house/marriage, was 'best for her'. You now see that maybe it was a flawed assumption (or not), but still, she deserves to know it was your intention, i.e. doing what was best for her.
You can also express the belief that of course "if [you] had it all to do over again, there are lots of things [you'd] do differently"---which is not a wimpy thing to say or an escalation of anything.
BUT LUKE, please don't OWN the divorce with that^^ remark. It's meant to show that you are changing, but not that you were "the ONE" responsible for the demise of the m. Nor are you to blame your w, in front of your d. AS SAID, the comment about doing things differently, is pretty authentic for you, or so I think. Do you agree? (It's your call)
Luke, just for me to be clear, imagine this scenario:
You are suddenly "placed" in this marriage instead of having been here for decades, & somehow, in some way, you KNOW that your d will not be harmed more by the choice you make about the marriage now,
the choice being to remain in THIS m, or to leave it...
I like to think you'd leave it...am I wrong? Dig deep and find that answer if you can. IF it's true, let your d know that, let her know SHE (and son as well) was a huge factor in your choice, if not THE ONLY or the biggest factor.
Let me break down what is the biggest fear here...RE your daughter.
Is your biggest concern that she needs to know how much you care for her?
OR, regardless of whether she knows you love her, is your biggest fear that she genuinely does not enjoy being with you;
OR
that her opinion of you is so influenced by your w, that she won't even like or respect you...
OR she does not know what she means to you AND some/all of the ^^above, too??
These ^^ answers will help me to advise. Luke, You really can do this.
M: 57 H: 60 M: 35 yrs S30,D28,D19 H off to Alaska 2006 Recon 7/07- 8/08 *2016* X = "ALASKA 2.0" GROUND HOG DAY I File D 10/16 OW DIV 2/26/2018 X marries OW 5/2016