I'm in this relationship right, my boyfriend can't find to trust me anymore because he found out that I told one of my ex that I still love him, but this happened in May now it's November he still don't trust me. Should I stay or leave and I really do live him.

Talk to your boyfriend. Confront him and tell him you need him to trust you. Tell him you love him and that you would never cheat on him. Ask him if he honestley trusts you and if he says no tell him you cannot be in a relationship in which he does not trust you.
Good luck :) I hope everything works out. <3

Were you dating in May when you told the ex that you loved him?

If you were, then I'm sure he's feeling a little insecure in your relationship. You can't force anyone to trust you... it's just something that will happen with time if you continue to behave yourself.

It won't help to tell him or threaten him. Just remember that your actions speak louder than words.

I think you should stay with him. My boyfriend was talking to a girl at the beginning of our relationship and I caught him saying things I didn't like very much. I was going to leave and you may think I'm stupid for staying, but he has absolutely nothing to hide from me anymore and I can trust him with all I have. As long as you both sit down and talk about things you guys will be fine.. it may take sometime to gain trsut back.. but it will come. Trust me.