B - kwym.
My dh is a fab step-parent to dc1 and we now are lucky enough to have dc2 (together) - he calls dc1 his own.
He's amazingly good at many things, bathing the baby, paying me the odd compliment, organising dc1 birthdays etc, finding good family holidays and family fun times, helping with hwk, earning a decent wage, making me a cup of tea EVERY morning (though that's partly self preservation, as I am very unpredictable without caffeine )occasionally cooking at the weekend, enabling me to waste days on the computer, organising mortgages, doing his own washing (I refuse - do washing for 3 other people with no help, plus b4 we were together he never had a problem finding his way around a washing machine)
BUT
Although he is capeable of pushing around a hoover without causing himself permanent damage (lol) he is utterly utterly crap unmotivated when it comes to housework. V. ironic as he often talks about the HUGE mortgage we have in order to live in our lovely home, but is unable to maintain it's loveliness iyswim.
It can be so bloomin frustrating, specially as he is a housework terrorist - he heats up the curry on a Friday night as a treat sometimes, but I usually end up scrapping it off the kitchen for the next week ...
Sometimes it just seems easier to do the wretched jobs yourself, while waging a gorilla war!
I did spoil DH by him not having to do much of the grind with dc1, but then he wasn't around when dc was small! We both work FT and v.similar hours...
I found the dog training principles worked well - lots of praise (for anything), lots of rewards and 'oh, i love it when...' plus ignoring negative behaviour, but it's a high maintenance programme and since dc2 splashed down I haven't had the time or patience to invest (at my cost).
Like you I find it hard going at times and am yet to find a magic bullet, laying down the law just has the opposite affect (stop oppressing me - teenagery whining voice) but, God love him, he was just the same b4 we got together under the same roof! Now I spend time warning single female friends to look out for men who DO do their own housework, as they never rarely change!