I think he still loves his baby mother 😲

My boyfriend is quite a bit older than me I'm 21 he's 34 . He has 3 kids with someone else .  And I have no children. And I'm kind of thinking he still has feelings for her . Sometimes I think am I overreacting? or am I just blind to it because I'm in love .  Take for example : He posted a picture on Facebook and she texts his phone and says "you look really handsome in your new pictures but that beard I'm not feeling it". I seen it and freaked out . He assured me nothing was going on and he loves me and I have nothing to worry about. So I let it go . Last night she called and asked him was he coming to get the children and he said yes . As they were discussing the pick up arrangements. She asked him "Do you have company" He replied yes and she said "Blah Blah Blah ; you know what I think I'm going to get a boyfriend because back then it was so easy to handle the kids and now it's hard " . I didn't say anything but I asked him about the little comment she made and he said "yea she was trying to make me mad but I don't entertain it ". He always tells me honey do you think I would bring you around my children if I still wanted to be with their mother or he'll say dont you think if there was something going on between us she would tell you . Sometimes I do think she's jealous because I'm 21 with no children and basically still in my prime. And she's 28 with 3 children still living at her parents. Or maybe it has nothing to do with me . My man just might be entertaining her . I want to believe him but it's wrecking my brain because I can't be there 24/7 to see what their texting . Please help 😩😩