Scared of bringing my ex back around

My SO and I recently got back together after taking a break in our relationship that lasted almost 6 months. My parents knew about the break but my mom is hellbent on the idea that my SO is this evil person who broke my heart and isn't worthy of my time. It makes me a little skeptical to bringing him back around because I'm afraid of how she'll react. We took a break because he's currently trying to get into grad school and he felt his work was causing him to ignore me and neglect our relationship so we both agreed to just take a break, but to my mom that translates to: "You put your work and studies above my daughter and that makes you a terrible person.". Any advice?