Should I (30F) tell my boyfriend (35M) I hate his mom?

I’ve been with my boyfriend for about 3 years now and have grown to dislike/hate his mom over the years.

It started as just thinking she was eccentric and a little kooky because she’s super obsessed with her dog, believes in some silly conspiracy theories and loves preaching about spiritual healing.

Then there was an incident 1.5 years in. We were on a weekend trip together and one night when we were chatting one evening she started talking about how she believes in karma, like if you’re suffering in this life, you did something to deserve it in your past life. On the face, not a crazy belief. So I said that makes sense but it’s hard to accept when you see children who suffer due to illness or abuse. But she didn’t back down. Basically saying they deserve it.

My boyfriend then jumped in and disagreed with her, saying that if she believes that, then she believes that his stepbrother deserved to have a mental episode at 20 and be placed in a care facility for the rest of his life. She basically said yes again. He and his stepbrother were very close all through childhood, so to hear her say this was obviously very hurtful.

To diffuse the conversation he just asked to switch topics but she wouldn’t let it go, saying that he can’t just stop conversations because he disagrees. It escalated and they got into an argument that almost resulted in us leaving and driving back home. They spent a few hours apart to cool off and then chatted in private, then all was fine the next day.

He told me that she didn’t really apologize. When he was younger they clashed a lot and he always apologized but felt that this time he really didn’t have to, and I agree. It all left a bad taste in my mouth and changed the way I see her.

Since then, everything she does gets on my nerves. She didn’t get him the cake he wanted for his birthday because they didn’t have it where she went. Annoyed. Threw a ridiculous 1st birthday for her new dog and we had to go. Annoyed. Calls him multiple times when she knows we’re out together or he’s working. Annoyed. Insists on making brunch for my birthday and then messed it all up because she thought she could just double a baking recipe and never checked or tried it. Annoyed. Doesn’t cook specific things for her husband that he would like because she doesn’t eat red meat. Annoyedddd. I could go on forever.

I don’t like that I feel this way and I think it’s exaggerated because my boyfriend is either indifferent or feels bad because they didn’t have the best relationship growing up so he’ll excuse some behavior. But I don’t think she’s a great person… It affects the way I act when we’re all together, like I can’t help but be low energy and just want to leave as soon as possible.

I’ve always wanted to have a close relationship with my in-laws and this really bums me out. We do have nice moments together, but it feels performative. I don’t want it to get worse and have my boyfriend notice because he’s so good with my parents I obviously want to do the same for him. I don’t want it to get worse and affect our relationship.

Should I talk to my boyfriend about how I feel about his mom?

TL;DR: My boyfriend’s mom hurt his feelings by saying something hurtful about his stepbrother and now I dislike her and get annoyed with everything she does. I don’t want it to get worse and affect our relationship.