What should I do? Please help

Me and my boyfriend lives together .. We are trying to have our first child now that I'm off birth control . However I find that he writes a female  on a social network he used to date asking her how she been .. I asked him about it but he said "he is going to have female friends" There convo was innocent but why does he need to hit up a old "thing" is my problem. Idk if I'm jus lookin for a perfect man or if he is playing games which wouldn't be the very first time .. Idk