OP, there's nothing at all wrong with preferring to be single - it suits some people better.
There's nothing at all wrong with having kids and dating, too - it doesn't mean you can't put your child first. As we all know, there are women who prioritise a man over their kids, but that can be the bio father just as easily as a later partner. It makes them a bad mother, it doesn't mean women who date are all going to do that.
I do think you might need to reflect on the fact that one day your kids will grow up and be independent, and if you centre your emotional life totally on them, then that is a huge burden for them to shoulder into adulthood. And very gently, it's also the case that loving your children is low risk in the short term - they can't leave you or cheat on you - but it could be very high risk in the long term, because if you do your job right, then they are guaranteed to leave you to build a life in which you are a peripheral figure. My MIL is still enraged about that (admittedly she was someone who prioritised her love life over her son and expects him to be there when her love life imploded and left her bitter and single in her 50s, so he has rather lost out at both ends of the equation) and my DH has as little to do with her as he can as a result. It's a sad and painful outcome for all concerned. I'm not saying you aren't also building a rich friendship network and other interests, I'm just saying some women become so absorbed by maternity that they don't, and it needs to be a balance... for the children's sake, as well as their mother's.
Of course a parade of blokes shouldn't walk through the children's lives in any sort of parental role, but again, women who do that are poor parents making selfish choices. It doesn't correlate to someone being a single parent who chooses to date. There are plenty of parents still with the other who are fucking their kids up in a myriad of other ways, just as single parents have a smorgasbord of means in which to do it by virtue of their different life choices. Selfishness (whether overt or tacit) over core issues to do with their emotional security and most basic emotional boundaries harms kids.
I think ignoring their best interests in favour of our own is a pretty sure-fire way to do it. But extremes in either direction can do that - either treating them as a proxy for a deep emotional life with someone who has chosen to be there and can leave at will, or forgetting that they are dragged along in the wake of our own romantic choices, can harm them. So surely a happy medium, which for most women would involve being open to a love life while keenly aware that they must balance that with the stability of their children's home and emotional life, is best? Again, I don't think all women can or even want to combine dating and children and that's absolutely fine if they also build plenty of other interests and emotional investments into their lives. I abhor the idea that any grown adult must be coupled up to be happy or acceptable, and I agree it's way too prevalent as an idea. But you say that anyone who has a love life must therefore place their kids second, which tbh I think is a bonkers idea. It's completely possible to utterly prioritise your children, and to have a love life too. Women end relationships when they don't feel it's good for their kids all the time, and most women don't introduce the kids unless it is very serious, and even then it's not as a step-parent, but as someone in Mum's life.
You can screw up almost anything in parenting if you are too selfish to think about the impact on the kids, and care more about your own fulfilment and satisfaction than you do their best interests. This is just one of the ways.