More comfort in him then myself

Ive got a problem. im aware my issues are things i can take under control if i just do it but its hard. the little things get to me when it comes to my boyfriend. getting mad over him on his phone or going to hang with friends boy or girl really gets to me and i dont know why. im insecure and im aware. i see all the girls as something better and i shouldnt. i am amazing if i put my jealous self aside. but what do i do about seeing my boyfriend as a comfort blanket? i know its not a bad thing but to the point where being without him just for a few hours makes me go crazy could be a problem. i need to learn to trust and accept we wont always be together. he needs to be his own person and so should i. to make things better focus on the positives and less negatives. see that im worth it. that i have something to offer and thats why he hasn't left yet. ive never been independent. always depended on someone else. never like to be alone. i feel i cant function right when he's not around or focusing on someone else. ive made my three year relationship hell for a good portion of the time we've spent together. i want to change it and make it better. complete 360. along with changing myself to be a better independent,not relying on him or anyone for MY happiness,making the effort of more positives then negatives, not being insecure and more comfortable with myself, seeing that in the end he's still with me and only me. thoughts?