The destroying of the toys, totally normal IMO - unless it's on purpose. I cannot think of one toy my 6 yo boy has that is completely intact lol. They're just heavy handed with toys, esp ones aimed at younger ages. I don't think it's very fair if he's breaking the other children's toys though (although I would imagine in a family situation most toys would be shared) - if it's your boy's special toys I'd have a rule that if he breaks them he has to make it up to them somehow - use his pocketmoney to replace it or something like that. BUT the rule has to be the same for all in the house, otherwise he will feel like an outsider or guest.
As for his attitude toward you, in my opinon, your husband should be keeping on top of the way he treats you. My DS is from a previous relationship and, yep, his father teaches him nasty things about us - we even had the privilidge of having taunting/demeaning songs and nicknames made up just for us by his biological father lol. I tell you what, if my DS *ever* disrespected my partner, who does a heck of a lot more for him than his 'father' I would be "we do NOT speak like that to each other in this house". I just would. not. stand for it!!!
Despite the ex being a poo, we don't actually have too many dramas. I know there can be a lot of excitement and confusion at that age swapping between houses - mine is a mess after a visit with his dad and takes a good day to calm down. I think consistent consequences and discipline at your house may help.