Thormas ... I could dissect your whole post line by line But I will pick on this one as it is close to my heart.
I have been with my partner for over forty years ... I am happy with the way it unfolded (not that I am not choosing to be happy, I presume you are not choosing either, you just are.) We have had our ups and downs ... couldn't have kids and loss of an adopted son, and that our son for over ten years of his life suffered from serious bouts of epilepsy would count as some of the major downs. But without those downs I would not be the individual who I am today. [and for the benefit of Burl, my illusory intrinsic self]. We would not be the couple we are today either.
Thinking damn it was not your illusory self that made the choice is at the heart issue. Evolution has imbued us with lots of emotions ... including guilt and pride. And I am sure they are quite "useful" in an evolutionary but pragmatic way. But as evolution is directionless and ultimately purposeless these emotions don't make sense in the light of day.
Again when I met my partner back in '72, she was not my type. In Dec of '74 she made a pass at me ... suddenly she was my type. I was aware of the raging hormones passing through my body (as emotions) ... bonding my eddy with hers. There was no choice about it. And I am happy, again no choice, that it is the case.
Can I suggest when you think or use the word choice, have in the back of your mind in what way is it a free choice? Is that choice somehow independent of your body chemistry?