Could he be cheating?

ronnie β€’ Proud mommy πŸ‘ΆπŸ’™
So, I've been kinda curious if my boyfriend's been up to no good. Couple months ago i saw him DM this girl there wasn't any flirting but when I asked him about it he got all mad he said he knew her from school "supposably" and took me home and didn't talk to me til the next day, well he saw some guy message me and got so mad long story short he told me to delete all my social media and he did too as well. After that things were good, no girls were in the way or anything. Well recently he lost his car, and we haven't really been around each other too much but he does come over at least twice a week just depends if he works anyways I went threw his phone and saw this girls number and before I could read anything I asked him who she was and yanked the phone out of my hand and said "she's just one of my dumbass friends" and I couldn't really see the Convo but I did see him like triple text her like he don't even do that for me. And sometimes I give him the benefit of the doubt and i always tell myself if hes cheating it'll eventually come out, I hate going threw his phone I try not to anymore but I know if I go looking for something I'll get mad I know some things are better off just unsaid but does anyone else think this is suspicious or am I just over reacting?