Advice with paranoid boyfriend

I love my boyfriend dearly and I know he loves me he smokes weed has done since he was 14, he's not a waster as he's self employed just got his car has finally got everything he wanted, when I met him he was at rock bottom on so many drugs I try to look at it like I've saved him as he didn't have a job nothing like that when we met, we've been together just over a year, the paranoia is a massive issue in our relationship, he thinks I'm up to no good all the time all I do is cry when he's on a good day I'm the most happiest girl alive, he also suffers from ptsd I just need someone to offer advice I'm still learning his triggers but it's so hard as I also have a 3year old from a previous relationship, I love my man so much but days like today are the hardest and I'm just at my wits end he's got no reason not to trust me I do anything and everything for him but it never seems enough what do I do?