Baby mama

So I’ve been with my man for a year and his relationship with baby mama is constantly changing. At first they didn’t get a long well then recently with more communication they’ve become great co parents. I’ve never been uncomfortable with their relationship until recently when something came up that didn’t have to do with their child. They are doing things together as friends and it makes me uncomfortable. I understand their relationship is important for the sake of their child but it’s hard for me to accept them as anything more than co parents. It’s becoming harder for me to separate her from being baby mama and his ex. I trust my man and I know nothing sexual or emotional will come up but I still feel uncomfortable with it. Do you guys have any baby mama advice?