My husband is still in touch with his ex-gfs.I feel very jealous and insecure. Is my feeling justified?.?

Ours is an arranged marriage and we got married a year ago. During our courtship period he told me he had 2 girlfriends in past and had broke off with the last one 3 years before our marriage. They are also married and settled in different cities. He talks to them occasionally, say like may be once in 2 months. Sometimes chats with them online. He has told me that they just catch up with one another and talk general stuff. I trust him completely and know that he is not and will never cheat upon me. But I hate it when he talks to them. I also get suspicious bcoz I am not with him the entire day. I get suspicious that he must be talking to them while he his away at office or when I am not around. He loves me very much and is a very caring and a wonderful husband and vice versa. I have already conveyed it to him that I dont like that fact that he is in touch with his ex. But he says that he is just friends with them and I should accept that much. I know that I am being paranoid. But i feel very insecure and it affects my state of mind very badly. I get scared to tell him upfront to cut the contact with them. Whenevr I discuss this issue with him I get very emotional and start crying. So I avoid to raise the topic and subside my emotions. I have tried to ignore it so far. But I cannot stand the fact that he is still in touch with his past and I dont understand that why one has to keep contact with their ex's. Am I over reacting? Because I dont want to create an issue out of this. Is my feeling justified or I should just let it go?