Trust him or leave him

I feel so insecure in this relationship. I recently moved into his house and he is never home I’m always home alone. He has been acting weird lately so I went through his phone and just found messages about his ex from before we met. That’s not what got me insecure on his Snapchat he has her under a guys name I texted him about it and says he has no idea what I’m talking about that she is blocked. Later on that day I got a message from her saying that he has been texting her and begging for her back and he promises me he has never texted her since they broke up. What should I do? I can’t move out of his house because all my saving is gone I spent money on him. His sister says he is cheating on me for sure and his mom says that he loves me so much.