How do I get over my own insecurities?

It’s not that I don’t trust him. I genuinely don’t think he is the sort of person to cheat on me and purposefully hurt me.

But there has been times when he’s been an idiot. Like smoking drugs and trying hide it because he knew I wouldn’t like it because of my job. I found out, and calmly told him that whatever he does I’d rather him just tell me in normal conversation rather than trying to hide stuff like that. And then I’d be ok, rather than worrying.

It’s probably just my anxiety and insecurities that make me doubt whether he’s happy with us, rather than anything specific he’s done to make me think that.

I do love him so won’t leave him.

But we live together and I think sometimes he’s purposely taking his phone to the bathroom with him etc to not allow me check it....

I don’t want to be so paranoid and I don’t know how to help myself when I get in a state like this.