Yes, you marry the whole package, but that doesn't mean you need to A) submit to manipulation, and B) subject yourself to someone's beck and call, especially if they are a hysterical fool.
I was blessed with delightful in-laws, but I had to take the above approach with my own mother some years ago. Here is an important principle in family relationships: you will NEVER get someone to respect your boundaries unless you A) set them, and B) enforce them. The fact is that, until you set and enforce boundaries, your MIL will continue to try and manipulate you, berate you, and offend you. Like froggie said above, grandkids make a great motivator for good behavior.
Here are some good rules to set boundaries:
- I don't go anywhere unarmed, including your house. You want me to come over, I come over armed. That is not negotiable.
- I can't help you if I can't come over, and I won't come over unarmed. You want help from me, get used to it. You're the one asking. Beggars can't be choosers, and I am not inclined to help people who do not respect me. That is not negotiable.
- I WON'T drop my kids off where they are not properly protected, and I WON'T take them where I can't protect them, if such protection is not provided for by the home-owner. That is non negotiable.
- I WON'T have you in my home if you are disrespectful in my presence of my beliefs, or the way I live my life. Say what you want in your own house or away from my presence, but in MY house, MY rules. This is non negotiable.
- If you EVER criticize me or disrespect me to my children in front of me, or if you ever criticize my beliefs or the way I live my life to them in front of me, you will not see them again until you formally apologize and promise not to do it again. I won't forgive it more than a couple of times. If you ever do it behind my back, you will never see them again, as long as you live. This is non negotiable.