Quite normal imho for some of us. Imho it is part of the process of grieving. I wrestled with it for a while. What I found in the wrestling is that it is the feelings and beliefs behind the thoughts that actually matter most.
Why?
Bc it is an impossible question. Unless you have a time machine. (And if you do, a few of us might want to cadge a ride lol). It doesn't matter if you might have made a difference choice bc you can't unmake it.
But
You can wrestle with it logically and emotionally until you find the conclusions behind it.
And anything useful to learn that you can use now.
So, logically...
You are assuming the path not taken would have been better....but how could one know?
If your h had died, would you have felt the same? If I had asked you five years ago, would you have felt the same? If not, what is in the space in between that makes it different now?
Which experiences from those 20+ years are not linked to your h or marriage so you can tuck them aside?
What did you value before that you see differently now?
What is the lasting cost and how do you know how long it will last? Can you change any of that? Are the costs more about concrete things or intangible ones? Get specific....what are they? And what would you need to have or see now as benefits or fruits from those years that would make you feel significantly different?
Based on the facts you know...either observed directly or concrete facts...when does the taint period begin? Or end? How do other (reliable) sources see it?
What would need to change now or in the future outcomes that would change your POV if anything? And how much control do you have over any of that?
And given that you can choose your thoughts....that your perception is your reality...how does thinking this way serve you? What would it feel like if you mentally experimented with some different ways of seeing it?
What if you just can't ever know for sure? What if you are wrong?
And emotionally....
Scared...don't want to know the answer...horrified....appalled...tainted....loss....love. What are these emotions really about? And are they more about you or your h? And what are the strongest emotions? Fear? Anger? Blaming yourself? Feeling foolish? Doubt? Vulnerability? Self-worth? Grief?
And why do you feel so never/always about both the past and future? That nothing from the past is worth smiling about and that how you feel now feels permanent. What do you get from feeling that way do you think?
What is the essence of the taint, do you think? What does it look/feel like? Either/or or a spectrum? More associated with some things than others? Triggered by some things more than others? Less about some things than others?
What are the differences if any between what you think, what you believe and what you feel right now? And how much of that comes from you or from what you think others think, believe or feel? And can you quarantine yourself from any of that?
And if there were a doorway to the possibly untainted, what do you think that might be?
I have no answers bc they are your questions.
But I can reassure you that I was in exactly the same place and wrestled with exactly the same questions. For me it was like a jigsaw on a table that I kept cycling around to see if I could find a missing piece that fit. For me it was a mixture of grief, acceptance and finding my own reality.
And I found that there was useful stuff that was part of my healing process that came from that wrestling.
I seem to be currently doing what feels like a last circle around the jigsaw pieces now but it feels different. Less emotion and doubt, a kind of process of picking bits up, looking at them closely in a way I couldn't before and deciding what to purge, ignore or pick up and put in my pocket. Onevof the biggest differences now I come to think about it is that it no longer feels like a process which needs any input other than mine. Which is just as well lol.
Martin Seligman, the positive psychology guy, talks about the three Ps that get in the way of resilience - personalisation, pervasiveness and permanence. (Sheryl sandberg talked about these too after the death of her husband). That what eats our resilience is believing that something was our fault or that we could have prevented it; that it seeps into every bit of our world view so it defines us; that we believe how it is now and how we feel will not change. These are normal beliefs in grief, trauma or depression. But they are rarely objectively true and we can train our brain to think differently. And we can look for the small bits of evidence that challlenge our thinking.
Which of the three Ps speak to you most right now, Anon?
How much of what happened was bc of you rather than happening to you?
What are the things about you and your life which were/are separate from it?
How have you/things stayed the same or changed (for good or bad) since it happened?
So I send you a wrestling hug, some encouragement that this time too will pass and a reminder to up your basic self care if you think you are lingering on the edge of depression and find this time of year hard.
....mostly I just send you a hug x