how to stop being Dramatic & Assuming

How can I stop being dramatic and assuming I only ask that because my boyfriend and I got into a huge fight and he said that
"You're too annoying and sometimes too nice. You assume things too much and you get invoked in a lot of drama."
Now I admit it I have been getting into a lot of drama and the result of that's is me getting angry and needing to vent. 
Then Some nights when my boyfriend is coming home late at night (Police officer) I can't shake the feeling he's doing stuff behind my back. 
So how can I stop being dramatic and assuming?