How to find out if he’s cheating

so for the past 6 months my man has been very weird with his phone won’t let me near it sleeps with it under his pillow doesn’t leave it on charge unless he can see it he thought my phone was his once and he stacked it so fast i was like wtf i go on his insta and he’s liking half naked girls ok i went about stalkerrr and went down his following and was just clicking on girls profiles to see if he liked any photos we did have an incident last year after i gave birth i had and and he wasn’t listening to mw a was crying myself to sleep each night he went to the shops and left his phone my son asked me to add his dad on roblox for him like except his request and i saw an email saying that his tinder profile was set up i couldn’t find the actual app and he claimed he downloaded it to see if he would get any attention because i made him feel ugly with all the crying and all i wanna do is talk i felt like pure shit he claimed he never spoke to anyone idk if that’s true it got back to his dad cos i kicked him out that night and his dad asked why and his dads reply was well she’s over reacting it’s like porn u was just looking u didn’t act on it and now everything is just weird he don’t wanna touch me when he’s in the room with me he’s on his phone and i can’t even make a phone call on it he’s basically always here but does every no and then say he’s going window shopping or round his mums i never know if he actually goes am i over reacting he don’t see the big deal with liking half naked girls but moaned at me for having my cleavage out in one picture i posted he basically calls me crazy and says he has no time to cheat cos he’s always here but something feels weird