moving in together

my boyfriend comes home from basic tomorrow and he has been gone for 6 months. before he left we decided that he would move in with me once he is back. the place we decided on I cannot afford on my own and he knows this. now he is saying that he might just want to stay with me for a few months. we have been together for almost 2 years and we have talked about get married and things so I just don't know what's up. 1. this really screws me over financially and 2. why did he leaf me on and is now backing out?