My boyfriend says he loves me but he cant see us working out long term. he was with his ex for 3 years and he thought that would last so maybe hes just scared or something.?

If he says that he doesn't think it is going to work out in the long term than you are probably doing something to annoy him. The best thing for you to do is change every facet of your personality to make sure you are the perfect girlfriend for him. Try making him breakfast in bed, doing all the cooking and cleaning, or taking his penis up your anal cavity. Remember, the less reason you give him to complain the longer he will stay with you. Or at least until he gets bored.