Should I stay,or should I go?

My boyfriend and I have been together for about 3 years now. I was fifteen when I met him. He was twenty. He’s a major pot head (well he stopped smoking) and he has done a lot of drugs in the past such as E,Shrooms,Acid,Cocaine.. nothing with needles though.. He’s never been hooked on any of them,but he has been a pot head for a long time now. His father and him have moved from place to place since he was five,and he has a hard time of holding onto people,or caring enough for people he knows because of it. He has told me personally that he lets go of people so easily because he always just ends up losing them and either getting hurt or them getting hurt because of the always “sudden moving.” His dad would wake him up and say “get up son were moving”,because he was in the Navy. Anyways,he is a very sweet guy but he seems confused with a lot of things. That includes me. I know he loves me,but I’m not sure if he’s gonna stay with me.. He’s addmited he doesn’t plan on staying with me forever,and I don’t hate him for it,because it’s his life,and it’s very understandable.. but my happiness counts too. He’s not stopping me from doing anything I wanna do,I just don’t know what to do! I should follow my heart but I’m getting a blank.. Within the past two weeks he’s been GREAT to me,taking me out,being quite the romantic.. but before that we were BLAH. Not bad or good.. just BLAH. No sparks really. He would sit at the house,play vid games,and smoke. And I’d be there with him,neglected.. I just don’t know what to do anymore.. should I just move on and wish him the best of luck?Or should I wait it out and be patient and let him make the deciscion?

Anyone have personal advice?