Should I end my relationship?

I have been with my partner for over a year. When we first started our relationship he was ringing her almost every night. On speaker and included me in the calls. When I met her she was flirty towards my partner, competitive towards me and was continually bringing up their relationship including sex. I was no longer comfortable with him keeping so much contact. So he would only ring her when I wasn’t there. I told him I was not comfortable with that and he said he would stop talking to her. Stupidly I said I didn’t want to stop their friendship but he should also ring when I’m around not only when I’m not. He has rung her again with me not around. Everything else in our relationship is good but i feel like he allowed her to disrespect me and i feel he is disrespecting me .Should I just walk away ?