OP, you have a daughter and a good relationship with her. Chances are, she'll be there on your deathbed.
I'm single and I don't have any children. My friends will likely be too busy dying themselves to come see me when I'm dying.
I still don't regret being single.
I've had some long-term relationships and when I compare and contrast those to my life now, it's a no-brainer. I'm so much happier not compromising my wants and my values every single day because society thinks I should be coupled up. Even when the relationships were 'good', I was still compromising myself to some extent.
People say that you do have to compromise in a relationship... but the thing is, you don't have to compromise when you're on your own. And there is nothing wrong with me for not wanting to suppress part of myself.
Previous partners have been demanding of my time to the point where I was made to feel guilty for having a career with long hours and occasional travel and where I couldn't do any of the activities I wanted to do because they clashed with the time they felt I should reserve for them. I'm a woman. I face discrimination all the time and I shouldn't be doing anything to compromise my career and earning power as I'm starting from a disadvantage.
I had to spend my money buying things that I didn't want to do (namely expensive food and alcohol). I didn't save money being in a couple - it cost me money.
I felt under pressure to always look a certain way (part of this may have come from myself, but I wouldn't have felt it not in a relationship). I wore make up far too often and I felt under pressure to make sure my legs and armpits were always shaved.
I found myself trying to adapt to their hobbies (including watching shows in which I had zero interest). Funny how it never went the other way...
I was never the best version of me, because I was always trying to be the version that fit with them.
I have some lovely male friends, so I know it's possible for men to be a bit less shit than this, but the risk v reward just doesn't seem worth it for me. I'm definitely happy being on my own. I could be happy in a relationship, but I wouldn't be happier, and I could definitely be much less happy.
I've been better off financially and emotionally since being single, and I wonder what a relationship could offer me that I don't already have. The only thing I can come up with is regular sex, but even that comes with its own hassles (contraception, pregnancy scares) and no guarantee it will actually be good (the men in my age bracket are no longer young, so I may well meet someone with ED).
Putting myself in a position where I feel compromised and judged, where I feel less financially secure, and all for the chance of some disappointing sex...? It's just a really difficult sell.