My boyfriend thinks he’s poly and wants an open relationship

My boyfriend and I have been dating for six months. We truly love each other and thought we would live together, have kids and grow old together. During our relationship we might have forgot about the importance of space and time for ourselves. I am very insecure and when he went out with his friends even during the day I freaked and asked if there were any girls and if he had cheated on me yet. He is very loyal and committed to me and I know that he wouldn’t cheat on me but I’m always thinking that he could find someone better looking or more interesting than me and leave me.

A week ago, he went to a political festival for five days with one of his friends and I didn’t go. He wasn’t on his phone most of the time because he wanted to learn and experience everything but I started feeling left out and got mad. We had a fight and the day he came home was our 6 month anniversary and we had a huge fight and I didn’t go see him because I made plans with my cousin and his grandma that I love.

Two days later, we talked it out but he found out that he might be polyamory and wanted to try an open relationship because it made sense to him to have more than one romantic connection. After a lot of crying and hurting we established limits but I don’t think I can go through with this and be able to handle him being with other people (sexually and romantically ). On the other hand I don’t want to break up because I want to spend all my life with him and only him because I have never had the special intimacy we have with anyone else.

can someone please help me? I have been devastated, crying all the time and feeling like my life is over.