Is my mother in law as awful as I think or is my partner right and I am overreacting?

Ok, so I’m a first time mum, and my mother in law has always been overbearing and opinionated but she’s got a million times worse since I had my baby. One incident that stands out in my head was that when my baby was 3 months old she decided she wanted to take her out without me. She didn’t ask me about this, but just messaged my partner and said that’s what she was doing. This is my first baby and I had a traumatic birth so I wasn’t ready for that, also, at that time I wasn’t going out much so I’d be at a loss myself without my baby. I explained this to my partner and he went on and on about how his mum was just trying to help and how I was being totally mental and unreasonable. He messaged his mum saying that I would go out with her and my baby too. She messaged back saying “I just want to take my grandchild out by myself without her, is that a problem “. Now instead of defending me, my partner sent her a grovelling message saying “it would really help helenaseas out if you let her come along with the baby as well”. I was so upset at this, it seemed so cowardly to me and he didn’t stand up for me at all, but he says I’m being stupid and his mum means well and that no one else would be upset by this, so I’m curious to see what people think. There have been so many more incidents but this one stands out. via /r/Parenting http://bit.ly/2GV8aZr