HELP!! am I too insecure for a relationship?

kss

so this morning.. like a crazy girlfriend, I went through my boyfriends Facebook and Instagram to see who he’s following..... basically nothing but females and random pages like university CHEERLEADERS, not university football..... idk why it makes me so mad. well actually I do, because I’m VERY insecure and have been cheated on in every relationship I have ever been in. am I just crazy? Also, one time I glanced over at his iPad and saw a screenshot of him and a girl on FaceTime. I know the girl so I know they’re not related or anything. He tried to lie to me and tell me I didn’t see what I know I saw with my own two eyes. Then went on to say he had “accidentally screenshotted a picture of her face on Facebook when he was scrolling” idk if I’m just paranoid and insecure because of my past or if I’m ignoring the signs to leave him!!