My current don't want me to be friends with my ex


I recently got out of a 3 years relationship about 3 months ago.. We remained friends but we are no longer in a relationship.. The guy am currently dating is acting insecure cause my ex still calls me.. He also said its strange that I said I would tell my ex when I am in a new relationship. It's a bit difficult for me to cut him off cause we promise each other we would remain friends after the break up...

Guys do you think that's a problem? Should I stop talking to my ex or can we remain friends? Ps I am really interested in getting serious with the guy am currently dating