My ex traumatized me but I let it happen

I was 19 when I caught my cheating bf at a planned parenthood. Me and my bf had been dating for over a year at this point but it felt longer since we spent EVERY DAY together and he would sleep over at my parent's house almost every night. One day he got off of work early and said he had a doctors appt. I was free that day and offered to join him but he was like "Noo it's ok baby, I don't want you waiting for me" I didn't think much of it..until he sent me a Snapchat. We were snapping back and forth throughout the day and then he sent a random picture of the floor. Mind you, he didn't know I was VERY familiar with this planned parenthood because that's where I would go for testing and birth control. When I saw the picture my heart dropped and I thought "there's no way he's there rn" I got in my car and best believe I drove 30 minutes away just to catch him in a lie. When I pulled up, sure enough there he was. His car and his plates. I waited parked next to his car until he came out. He had the most confused/shocked look on his face and I was just standing there smiling. (I laugh when nervous or angry)...he then proceeded to make up a reason to why he was there, we argued and I sped off as he followed behind me..my stupid, young naive ass took him back a week later after finally giving in to his apologies and begging. Worst mistake ever. Fast forward another year he's living in his own apartment...like for pt 2