Is he cheating

So first of all im not dumb I listen to these feelings I get. Anyways I grab his phone he quickly snatches it from me. I say okay?? Next attempt...I got it but he again snatches it right back. 3rd attempt I try to be smarter grab it while he's sleeping. I go sneak in there I grand it i make it to the bathroom I turn it on and boom the door is just about kicked down and hes all oh did my buddy text me and snatches it away. I said why are you snatching it away that's a red flag he said. If you want to start a fight then just effen leave.... like dude. You never snatched your phone from me except that last 3 days.... ps he really really guards it.

Update

I would like the phone because we'll I innocently went to use it and got it snatched from me. So now I want to see what's on there. He always let's me go on his phone but the last few days I can't even touch it. He's cheated like this before he has a problem with sexting and texting other girls. So I'd like to know the truth that's why I'm looking through the phone, if it's true I'm gonna leave. He snoops through my phone constantly through my Google account he doesn't think I know but he can search mine but I can't even touch his??

And no I'm not his mom I'm a women looking out for MY feelings.