My BF keeps talking to his FWB

[somtuta]

what do you do if your bf start talking to his Friend (with befits) as a “friend” that he was with 3 years ago, or what do you think about it. He told me once that she was his best friend back then and that woman liked him but he already told her from the beginning that he doesn’t want any commitment, he told me once that he like her very much but he doesn’t want any commitment as he told her so... He said she is very kind. She understands him very much what he has been through. Blah blah blah.
At first he kept talking to all his FWB back then I asked him who are those people and he said, they were friends. I found out about it later and I was sad and mad then he lost contact with all of them. Anyways, after he met me dumped her and all his FWB and came to me. And for no reason after 3 years he wrote to her (He didn’t keep it secret from me. I can check his phone freely and I found out about it after they have been talking for 6 months and the day he wrote to her was the day we argued quite seriously).
He asked me reasons that I don’t like about it and I said I just don’t like it. He was sleeping with her and I don’t want him to keep talking to her and I told him that he doesn’t care about my feeling. And then he said, you don’t care about my feeling either because you keep telling me not to talk to her, she is my friend. And he keeps asking me why I don’t like her and I can’t answer that. All I know or can tell him is I don’t like her. Do I need more reason than what I told him above?
Am i being a bitch if I am mad and not happy about it. Sorry about my broken English grammar.
I need third person perspective about this. I can’t think about it clearly.

[Peek_A_Boo]

R u indian cuz u fucking cant make sense