When is a good time to let it go??

Me and my SO been together four-years we recently went. Through some trials and ended up living in a hotel. For the past few weeks things have been changing she spends most of her time downstairs in the lobby not coming to bed til time for me to go to work. Shes changed her password in her phone her wallpapers and even made her message notifications private . Is she cheating?? We had convos abt this but it ends up nowhere but saying we gone try and then same thing happens the next say and im made to look like in just the naggy wife... im so confused i love her with all my heart and don’t wanna lose here but when is enough enough?