You need to tell your DH, in no uncertain terms, that his parents' behavior is NOT OK, that you are his wife, and that he needs to respect you and your feelings and boundaries. He needs to talk to his parents. If he can't, then I'd suggest some counseling for you both, but beyond that, I'd just tell the in-laws that they are not to come to your house and you will not visit them, period.
I don't mess with my kid's security. My dad, for example, shouldn't have had the kids he did, let alone be left alone with my son for more than a few minutes at a time. He's a great grandpa, but he lacks good judgment (like the time he put my son in the trash to tamp it down - Jack was 18 months old).
You really need your DH in your corner. I hope that happens for you!
