Cannot believe what SO's ex said to me

SO has a child with his ex. We are civil and can do things together for his child so we always do halloween together because of his childs siblings. Biomom is passive aggressive towards me and just plain attacks when talking to him. So we show up for Halloween. I have been letting my hair grow out so it is healthy. I have dirty blonde hair that looks brown. My SO likes blonde hair and BM is natural blonde just a few shades lighter than my hair but colors her hair to platinum blonde (btw i have been coloring my hair for years and have always done light blonde and met when him my hair was that color i didnt change it for him nor did i know he was i to blondes). Anyways we show up and she was like omg your hair its brown. I just said ya im letting it grow out because its pretty damaged(from a bad dye job i had to fix from a professional). SO was standing right there so she said it looked good and it looked like an ombre effect. Just backstory so you know what is going on she is now divorcing her husband who was there as well because they have a child together. So later on we were standing there together just her and i and she said you know he only likes blondes (talking about my SO) and i said ok and she told me that he would still prefer her over me anyday because she is natural blonde and he hates brown hair. She seems to think his love for me is based off of my hair color and that he wants her back because she has blonde hair. My hair is not brown i was born with platnum blonde hair it just got darker over time and is still not brown but anyways since the kids were there i didnt say anything not wanting to start problems so i walked over to my SO and stayed with him the rest of the night. Later on that night she is constantly texting him and i told him its late if she isnt saying anything important that it can wait and we can "go to sleep". I was in the mood to get some so he stopped texting her and she blew up his phone with 15 texts and 5 missed calls at 10:30 at night. I swear this Bi*ch is trying to get under my skin. He already deals with her craziness so i didnt tell him what happened but i feel he should say something to him about her always trying to talk to him when it has nothing to do with their child and to just keep things civil with boundaries like things had been while she was with her husband.

Edit to eve: im not because i know my SO doesnt care what my hair looks like but apparently she thinks he does and i just find it disrespectful to say something like that to me while the kids are there and we are just trying to have a good for my SO's child and then trying to get his attention afterwards. We are engaged so i dont have worries but i think he needs to tell her that the same boundaries apply as when she was with her husband because he is with me.