How do you feel if you found out that your husband complain your parent in internet forum? Would you accept it?

I agree with Ameetess. Open communication is always always the key. But do understand that maybe he is also thinking that you might get hurt if he shared with you his concerns with your parents. This might be his initial thinking. Just let him know that you are very much willing to listen--whatever concern it maybe--because you are his partner. And that you would understand him and help him no matter what.