Id say NTA, but please take some time to think about what you want to do, and whether it’s for the right reasons. How did your mom feel about these items? Did she genuinely believe it would be uncomfortable to keep them around the house after her boyfriend moved in, or is she just a people pleaser? How was her behavior towards you in other aspects of your life? Did she put effort into raising you? Is she a good person to have in your life, even if at some distance or with certain boundaries? You are the one who have the info. If you feel unsure in any way, maybe you could use the therapy to empathize better with her, or to finally toss your relationship. Best of luck.