Future mother-in-law mad I found my wedding shoes while shopping with her son's (my fiance's) stepmom?

I was out shopping on Sunday with FH"s stepmom, who has been nothing but kind and supportive, the exact opposite of FMIL. We stopped in a shoe store as a lark and I found my wedding shoes! Word got back to FMIL and she is PISSED. She says I never want to do anything with her, esp wedding stuff, she says I do it all with my mom or "my clan" as she calls my family (and why would I like her after she calls my family that?). Firstly, I don't like the woman, so no, I want to spend the least amount of time with her as possible, two, I have every right to do wedding stuff with the people that I love and care about and who love me back-FMIL is not one of those and I am not going to include her to boost her ego or make her feel better. Thirdly, who I spend time with is none of FMIL's business and who I was with when I got the shoes does not concern her.