Why do I feel uncomfortable when my boyfriend is around his ex because of their daughter for a period of time and he doesnt want me around?

It sounds as though you're experiencing a time of feeling very insecure about your relationship. Whether it's new or untested with different problems or just not as strong as you'd like it to be, having your boyfriend spend time with his ex without you around causes you to think of all the "what ifs" that come up with that scene. Perfectly understandable. Your boyfriend, if he's a stand-up guy and mature enough to sustain a relationship, should take your feelings into consideration. You might want to talk to him, ask him to include you in the visits with his daughter, and hopefully get a positive reaction. If you don't, you might want to think about whether you and your boyfriend see your relationship differently and whether it's one you want to continue.