Can a 21yr old groom a 18yr old

When I (now 24f) turned 18 I got into a relationship with a guy who was 21. We did flirt a little when I was 17 but didn't date until I was 18. I was living with my abusive parents and ended up moving in with him shortly after getting together. He said he'd never treat me the way they did and he'd give me a happier life and I practically saw him as my night in shining armor. Then it started getting abusive after awhile. We ended up being together for almost 4yrs and everytime I tried to leave he would manipulate me and guilt trip me and I pretty much felt trapped. I felt like he used my family situation to manipulate me and prevent me from leaving.