Ex bf and best friend

I had a best guy friend that turned to my bf and then into an ex.

I still love him but we really have a lot of relationship problems. Is it bad for my heart if i try to remain friends with him (i didnt want to but he asked and i gave in) and we ended up teasing each other sexually over the phone.

He asked me if he could come over (because i agreed we could be friends while i still love him) and spend his weekend at my place. I said yes thinking that im gonna stand my ground for sure and only treat him like a friend. Unfortunately we escalated into having phone sex after few nights talking otp.
(He said i could call him anytime at night when i cant fall asleep and it actually helps because i was used to this during our relationship) i was having insomnia because i was really distraught about our breakup.

Im hurt that he could still suggest we could be friends after our bad breakup but i still folded for him. Is it good if i gaslight myself to think im just using this opportunity to fulfill my lust for him and force myself to be cold about myself still being in love with him. Do u think i would get even more heartbroken in future? I was trying to cut him off to move on and had a depressing phase because i had to control myself from talking to him to detach myself.

What if we stayed friends with a little benefit? Should i be worried? But i really like being around him because he was my best friend nonetheless and he helped me emotionally when i shared my family problems and he could understand me. I dont wanna lose someone that understands me so well but i dont wanna lose myself from getting hurt again. Thoughts? I really need advice.