relationship advice

So my guy and I have been dating for 7 months officially and have been friends for the past two or three years. I love him very very much and he loves me too. Now recently I have lost my two closest best friends. I'm not sure what I did to make them leave cause they had cut me off completely. I've been very very down about that and I think it may be effecting my relationship as well. I have grown very paranoid of losing him and him cheating on me. I've talked to him about it, but I'm scared I'm not good for him and I'm just gonna end up ruining him. Any thoughts?