Help Need Advice ASAP,WHAT SHOULD I DO??

💫👶Tk✨👣 • Let Go & Let GOD,Our Blessing will come eventually
Me (19yrs old) & my bf (19yrs old,fina be 20 in July) of 3years going on 4yrs when October come,just recently moved in our new apartment I go through his messages on Facebook he telling some girl he got his own spot & she said who u live with he said it's just him she live over here cause i saw the name of the apartments also,so basically she live in my apartments somewhere but he been knowing her for a while,but I know he aint cheating he be with me 24/7 I inboxed her & said stop inboxing him b4 he be on the streets this my shit not his Even doe I love him true enough I feel like that's wrong that he lieing he could've said me & my girl or wife or something I wana ask him about inboxing her behind my back I'm just confused but he stupid cause I'm in my own shit,paying the bills so I can do way better than him I can get a nigga that have a car & job my bf don't got shit yet his family dont support him or shit so its like I been providing for him his mom let me move in with him when I was 17