my instinct tells me hes cheating?

what should i do girls? i have a really strong ass feeling that my SO is cheating on me. i swear he does a shit ton of suspicious things that everyone would feel fishy about it, even himself. he does things that a cheater would do. i just dont have proof. ik snooping is bad, but its also a good thing, cause i believe if u dont snoop, youll never know the truth. but i cant snoop, cause hes super secretive and defensive of his phone, when he wasnt before. and technologies nowadays are making it easy for cheaters to cheat. all tat fingerprint, private mode, private messages, and crap. i cant talk to him about it too, cause he refuses to, hed just make me the problem, and act aggressive towards me that i only want to ruin our marriage thats why i keep wanting him to reassure me that he isnt cheating. he also told me to leave if i need to know about his privacies. he made a vow that both couples should know each other privacies and have access to everythin. but after our separation, he broke it. i have found him do things he shouldnt be doing when he still lets me have access to his phone. like saving pics of ex wifes sis, having accts of sex/hookups sites, and browsing thru craigslist personals. idk what to do anymore, im going crazy not knowin everyday.