My boyfriend 31/M broke up with me 28/F about a month ago. He said he loved me, enjoys my company, has fun with me but doesn’t see himself spending the rest of his life with me.

In a lot of ways he is very immature and has always felt pressured when it came to being exclusive for every woman he has dated (has had 6 gfs) and has never seen himself marrying any of them. I walked away 2 months into dating because he wouldn’t be exclusive only for him to come back a week later and agree to.

When we broke up, he admitted to not treating me great and being insensitive to my needs. He said I was everything I wanted on paper, but there were no real boundaries in our relationship and he could just do what he wanted and faced no repercussions. He then said if I did set boundaries we would have broken up sooner. He said he felt like I was afraid to lose him during our relationship.

He was my first relationship and first love. Obviously feeling like shit with all of this and want to get better for my next relationship. There were times when I would bring up serious stuff in our relationship and he would just shut down - so I felt like I did try. He said I wouldn’t ask serious questions in our relationship but I did ask about moving in together and a future probably closer to the year mark of dating. I told him I didn’t want to be his mom having to nag him to do stuff and be up on his shit. I want him to give what he wants to me freely and assume what he is giving is his best.

Question - how can I set better boundaries for next time and push back? How can I be less of a pushover and avoid this for next time?

TLDR; bf broke up with me because he couldn’t see marriage. Red flags he had for me was that I was always so grateful and accepting of him even if he was mistreating me. I always assumed he was doing the best he could and wanted him to give what he wanted freely. How do I be less of a pushover in my next relationship and call them out for mistreating me without nagging?