What emotions do people feel about the relationship at the end of long relationships?

A feeling of mostly wasted time, but not massive.  It was pleasant and warm. It just did not go anywhere, and the ride okay, but not ecstatic.

I broke up after about 2 years after I saw the relationship 1) wasn't going anywhere - no greater intimacy, etc. and 2) I was no higher than #6 on her priority list, maybe below #11, with her work, school, science fiction friends, writing (she is a published author), family, and her other groups of friends.

I was the one who decided to break up. That did make it easier.
There wasn't any super emotional intimacy. That made letting go easy.

She would be perfect for someone doing a start-up who needed a articulate and  presentable girlfriend, but low drama and low maintenance.
Sort of like a Ford Taurus rental car.

(My God, that's the cattiest thing I have ever written.)
Actually, she was better than that, let's say a rental Lincoln.  But I did not get a feeling of ownership either way.

Why did I stay so long ? It started out more exciting for a number of months, and then it seemed both our work lives intruded...there may have been something else going on (another guy or girl) but there wasn't much evidence of it, not that I looked that hard.  It was very comfortable, until about the last year, when it seemed the relationship was riding on inertia. The last year did turn into friends with benefits (FWB) situation.

I personally have been very lucky in that none of my serious girlfriends was a psychobitch drama queen, or a druggie, or even mean. That's lucky for about 6  long term relationships, and a number of shorter ones.

So I did not have any painful previous wounds - I think that helps a lot.

I do wish her well, and I hope she found something that excites her and lives happily ever after. As Oleh points out (see comment below) Happily ever after is a Disney concept, and possibly not something that should be part of our expectations. Even if it is infrequent, I do hope she has it.

She is in NorCal, so I need to be anon here.
If my spouse cheats, and we divorce is it true that I'll get custody of my children? How much does divorce typically cost?

No. Your spouse being unfaithful was a transgression against you, not so much against them - although notably by extension - but likely will not affect custody... unless, of course your spouse decided to put the children in danger in order to cheat.Custody is weighed by a vast variety of factors, including but not limited to:Parent emotional

How to get over my narcissistic husband of 27 years

You allowed him to rob 27 years of your life plus whatever years it will take you to get over him. Keep the last part of him leaving your inner self short.

What is the best bodybuilding routine for men over 50?

The same bodybuilding routine for a40 year old30 year old20 year oldIf you don't believe me you can go check out Mike Matthews, he's one of more pronounced fitness professionals who talks about the older population & weightlifting too.What you do depends on your goals, It depends on