My mom keeps shaming me because I lost my virginity

I lost my virginity at 18 with my monogamous boyfriend. My mom asked me if I was still a Virgin and I told her no because I'm not gonna lie to her. And ever since then whenever we get into arguments she throws losing my virginjty in my face or shaming me because when I was little I told her I want to save it til marriage but things happen I chose to lose it. She keeps threatening me that she's gonna tell my stepdad and that I need to buy a purity ring because she doesn't want me having sexual activity while I'm living with her because there's another man in the house. Like I feel really alone and I don't know what to do.