Am I being jealous about my boyfriend's friend?

I am in a 7 months relationship with my boyfriend.  I love him so much and does too alot. He even want to marry me. So he has a friend ( a girl) from high school who he reconnected with her from 2018, it 2 years. So he used to talk about her alot on how she was hurt and he doesn't want her get more hurt by guys. The girl has a child with the other guy. I was invited to the birthday party by a friend  and i asked my bf if we will leave together and he said that he will send me the location. I was pissed , to a point that I didn't want to go but I went. When i arrive, i saw the bond the child and him had. He then, introduced me as future Mrs and I laughed. So as the birthday preparations done, he went to the friend's house and came back wearing a white Tshirt. When I arrived her was wearing a green vest. So I asked myself were was this tshirt at, friends room or what? He never entered my room but I entered to his. So I ignored it and act normal. As we about to sing,  the mother of a friend greet the friend's high school and I was asked " and who are you?" It felt awkward and my bf kept quiet. The bond the my boyfriend have in that family made me asked to much questions . So the friend's bf arrived at 4pm and I asked myself why didn't the bf be the one who organised the birthday but not my bf. I wasn't his first priority to him . Even the bf felt uncomfortable around my bf . So ever since that day i felt doubtful of him and I told him how I felt . He even asked to be her friend.