I guess I'm one of those who make your blood boil then Rhondajean, although I rarely start threads about it.
I met DH in the UK. He seemed very sorted, had been travelling for a year, was quite capable of looking after himself. We had a long-distance relationship for a few years as he was back and forth, doing a degree in his home country as a mature student - self-motivated, organised etc. He helped (ok, he was never big on housework) around the house, cooked, washed up, did his own washing etc. I thought he WAS a fairly mature adult.
Imagine my surprise when we emigrated to Aus with 20mo DS and got within MIL's radius and DH reverted to teenage behaviour. He's still a motivated worker job-wise, no problems there. But everything else has gone steadily downhill since we got here. And as DS has got older (he's 5 now) DH seems to be bent on being his best buddy rather than a proper parent, to the extent that they collude in badness (I'm the disciplinarian, obviously, which wasn't how I wanted it to be but someone had to do it!)
DH has nearly let DS drown by allowing him to swim in the lake with MIL, despite me warning them that this would be dangerous - his mum lost her footing and she was floundering, while holding DS. DH was baiting his fishing hook - luckily he turned round in time or they'd both have been dead (I wasn't there).
Week 1 of having a trampoline - DH was out "looking after" DS on the trampoline, but hadn't closed the net so DS managed to fall out onto concrete. DH picked him up and brought him straight to me, then left me with him. He can't deal with it! He doesn't try! And I can't force him to because DS would suffer while we argue about it.
The problem I have NOW is that DH just doesn't think first. How can you teach someone to do that? He just thinks about himself first, always. He's great when you tell him/remind him/ ask him to do stuff - but I don't want to always be doing that. I would love to be confident that DH could look after our sons competently but I'm not sure that he would, because he doesn't try to think about what they need (including feeding them).
Oh, and to complete this epic post - I asked him to change DS2's nappy in the first week or so; he'd done DS1's nappies before, so I expected he'd be ok - he left the nappy wrap off (cloth nappies).
I'm sure the purists among you would think I should somehow have known that he would be like this - but really, how? Until you're in the situation, you can't foretell how incapable of forethought someone is going to be, when they've seemed perfectly competent up until that point! And I don't enfeeble him - I encourage him to do stuff, think first, all of that - but he reacts like a teenager. So what - am I supposed to divorce him over that? I don't think so.