@NocturnalClocks
I'm happy to be corrected that my situation is unusual and most single mothers have willingly decided to have children with men who had already shown themselves to be incapable of being decent fathers/ husbands.
It's not just being "incapable of being decent fathers/ husbands" - there are lots of "signs" in other areas of life, lots of "clues" as to the true character of someone.
Such as whether they're aggressive/argumentative/insulting when they've had a few drinks.
Whether they have honesty/integrity in other ways - do they lie a lot about insignificant things, if so, they'll probably lie about bigger things too!
Before getting in too deep with someone, you really need to look at the whole character/picture of them. Not just specific aspects.
I remember my 21st birthday when all our office went to the pub at lunchtime. One of the typists brought her boyfriend, he bought me a drink and I already had one on the go, so left it on the table. An older co-worker (50+) mistakenly picked it up (it was a crowded table), and this girls' boyfriend went ballistic at him - really aggressively shouting, abusive, even threatening to punch him! We were all aghast, but he just sat down and carried on as if nothing had happened. She married him, had 2 kids by him, and of course, divorced him as he apparently started beating her up and hitting the kids etc. Sad, of course, but the signs were there - we could all see he had a temper over literally nothing!
My sister is also a good example! Her boyfriend was dishonest in everything he did - he was self employed and didn't declare his true income (flag 1), he never bothered taxing his van (flag 2), he'd often "forget" dates with her (flag 3), he was a typical "boy-racer" with his flash car, parked where he liked, ignored speed limits (flag 4), and so it went on. He was basically your stereotypical "bad boy". But for some unfathomable reason, sister thought he'd change when they got married, he didn't, then she thought he'd change when they had children, he didn't. Eventually she left and divorced him, but now whinges that he doesn't pay the correct child maintenance because he doesn't declare all his income! Duh! She didn't mind when he was a tax evader during dating, didn't mind the extra income when buying a house and living with him due to him not paying tax, but suddenly doesn't like his dishonesty when she's the loser and she'd not getting the maintenance she "deserves" based on his "true" income!