STUCK BETWEEN LOVERS, PLEASE HELP :(

When my ex-boyfriend and I broke up, I started catching feelings for my best guy friend. But I wasn't sure if it was because I really liked him or because I liked how he treated me better than my ex. So I told him, Im still confused about my feelings. I'm not as physically attracted to him than my ex. But he wants to help me get over him by letting him be in a relationship with me. I said no, I'm not sure of my feelings. He understood and told me he will wait for me until I get over him. But the thing is, my ex is talking to me again. He came over my house to study for an assignment we have a subject together. But things escalated and we started getting intimate, too intimate. I feel so guilty. I don't know what I should do. I'm not as physically attracted to my guy best friend, but he treats me like a queen. But I'm so attracted to my ex, but he can't give me what I deserve. And I told him I need time to forgive him. He's asking for chances but I know he will slack off eventually. He's waiting until I start healing. I saw my whole life with him but he keeps fucking up. What should I do in this situation? :/  I haven't told my guy best friend that I still talk to my ex because they both hate each other. But my ex knows about the situation between me and my guy best friend. I'm so confused. Someone please give me advice