Last relationship ended in 2014 when I was 41 and haven't dated (nor had sex) since then. Now 52.
Mine was a bit of a mixture of reasons.
I had my own stuff that needed sorted out with therapy from childhood. Didn't really twig what was wrong till my late thirties so....
Just being hurt or 'betrayed' or broken trust takes a toll on you. I thought I was taking a years break to recover and here we are 11 years later.
I got my first dog when I was 40 ish and was way less lonely as a single person with a dog than a single person without. They do keep you quite busy and out and about and the need for human company just shrunk.
Got busy with house renovation, renting out couple of flats and working part-time in finance too. After that I cared for elderly parents for 6 years and now they have gone I'm too bloody knackered to date.
All jokes aside I'm having a year or two to myself to get my health in tip top shape. Also the dog is getting old so giving him nice walks and spoiling him a bit. I also want to move house at some point so have to get a few things fixed/sort the place out. I am dabbling with the idea of giving dating one more shot once I get my health fully sorted and get over my exhaustion from all the stress.
However if my choice is dream home or dream man then I'm picking the dream house (plus another dog when this one goes).
If I get can have both will okay I'll give it a shot. Haven't gone through menopause yet so kind of hoping that will happen soon and put me off going back to dating at all. Don't know if that is because I am scared at the prospect of trying again or whether I just cannot be bothered with it.
I will be looking to be a bit more sociable in the future as looking after elderly parents is quite isolating but that might just mean joining a book club for some female company or perhaps a theatre meet up group or something.
I think it would be harder to give it up in your thirties than your fifties but I suppose I was 41 so not long out of my thirties.
I think whatever path you take you do think 'what if.......'.
I was married for 12 years from my twenties to mid thirties (no kids) so whilst there was for sure good things from being partnered up there was also frustrating things.