In answer to the OP, dh failed to put a condom on properly due to him being pissed and stoned.
I failed to do anything about it because I stupidly thought that nothing would really happen after one, just one, accident.
After dd was born, we thought we had better have another to keep her company. We both come from large families and couldn't imagine life without at least one brother or sister.
As we are not naturally paternal though, we do learn by watching others and making mistakes. We're quite disciplined, but fair I like to think. We had a routine fairly early on. If we say no, we never change our minds. We always back each other up (well mostly), though he is stricter than I am. We never offer an alternative for food, if they don't eat then they don't eat, no big deal. So we are fairly laid back, we don't worry about them all that much, but what we say in our house is gospel and they know it. I think that works for us quite well. But I'm not sure how we'd cope with more than 2.
dh has given up the weed now. No more accidents!