While even the Bible says that two people who are married "become as one" - and I strongly agree with that - there is a sense in which you remain individuals and need to stay out of each other's business. Handling a parent remains the business of that parent's son or daughter, not the business of the SIL or DIL.

You sound to me like a basically good natured guy who's trying to be a positive influence on an unfortunate situation. But there's something else I'm reading between the lines. Your wife has boundary problems. She grew up with a mother who was manipulative, intrusive and probably domineering. Your wife never succeeded fully in becoming her own person because her mom wouldn't let her. Her mom didn't give her the emotional room to appropriately detach herself from parental interference. (Probably because her mom feared abandonment.) Now your wife is letting you do the same thing her mother did.

Your wife would prefer for this to be a conflict between you and her mother than between her and her mother. She never learned how to handle her mother, so there is this big void - and you are stepping into it. Big mistake!

It would be far healthier, if your wife were to say, "Thanks for trying to help, Hubby, but she's my mother, and I'll handle her." She won't say that because she lacks the confidence. Your best role is to help your wife grow into a more confident woman. She'll end up being a better wife to you and a better mom to new baby. Even though your wife has angrily vented to you regarding her mom, secretly she wants you to stand between her and her mother. Step out of that space . . . step out of it. The, for the first time in her life, your wife will have the "room" and opportunity to figure things out for herself. At first, she's not going to like that. It will feel too unfamiliar to her. But you need to hang back and let her wrestle with Mom on her own. Fight the huge temptation to jump into the middle between them. That would be you treating her like a child. Let her grow up.

That doesn't mean you do nothing. Your job is to keep the bar up, in terms of what you have a right to expect as a husband. As A Husband. Whether or not MIL and wife can speak civilly to each other is their problem and not for you to make pronouncements on. But you have a right to choose not to be in the middle of strife and craziness. You have no obligation to meet up with MIL for dinner, if it does nothing but upset your digestion. Stay home. Let wife go spend time with mom by herself. I'm assuming your wife is capable of leaving the house without you.

If MIL comes to visit and is obnoxious, say you need to go check on something and go for a long drive, leaving the two of them to deal with each other. It's okay, since you live there, to limit how much time your MIL can spend hanging around. Do that, not by tellin your MIL when it's time for her to go. Do that by privately telling your wife, "Honey, I need your mom to get going because I've had about as much of her as I can stand." Then expect your wife to set a limit. As a husband, you have a right to have expectations as to how much craziness your wife is going to let her side of the family inflict on you. If it's too much, your beef is with your wife - not with her family, or any member of it. That's how you can be a strong man.

If wife comes home and says, "What on earth am I going to do about Mom?" - don't be so quick to answer. Say, "I don't know, Honey. It's a tough situation, but you're a smart lady, so I know you'll decide what's best." Show her that you believe in her. Don't keep doing to her what her mom did to her all her life - even though your wife kind of expects you to do just that. Handling her mom is her job and she needs to figure it out. If she asks for suggestions, when the two of you are alone with each other, you can gently make a suggestion or two. But leave the ball in her court.