Should i be jealous ?

me & my boyfriend dated for 8 months but we broke up cause we faught all the time. then a few weeks later we got back together, then after a week we broke up because he went to a party without my permission, even though we agreed no partying. Now he wants to get back together again, 3 weeks later, but this time were going to talk about everything, Lastnight while we were talking about what were going to fix he said he was still friends with the girl he was about to date the past 3 weeeks we were broken up, he said they agreed to be friends cause they liked it better that way but he also said he agreed to help her practice with softball once a week...i know if i ever told him i was going to go shoot some hoops with a guys once a week hed disapprove..so why is it okk for him to do that but i cant..& why am i so jealous. Hes never cheated before but i feel angry that he wants to go hang with her...what do i do