I don't know how to deal with this situation

I've been with my current partner for around 6-8 months though we have been on an off for a year or two. I love him alot and he's by far the best partner I've ever had but there's one thing that's making me worry, for the past few months it's been feeling like I'm stepping on eggshells. I can't say certain things and I certainly can't talk to him about something he's doing that's bothering me because he will just blow it up into a massive argument. I feel so lost on what to do as it's demonstrated that talking isn't a solution and I really have nobody else to turn too.

I used to have a vent chat in an app I frequented but my partner ended up reading all the way up it and finding everything I had said about him whether it was vent or general conversation, he was understandably upset that he was talked about since I did say some messed up shit in the months I had used the chat out of anger but now I genuinely don't think I can talk to anyone about anything. I have this lingering anxiety that he will find it or that I'm not allowed to vent my frustrations regarding our relationship since he doesn't seem to want to talk about it without bringing up all my flaws and everything I've done.

Even now if he was to see this I'm not sure how I'd handle the shit I'd get after,

Basically what I'm trying to say is that it feels like I'm constantly walking on eggshells and I cannot talk to him about anything. He's being way more moody with me without explanation and I just feel very overwhelmed with the whole situation, I have no idea how to approach it