Honest opinion plz!!

So my fiancé and his baby mamma still say I love u to each other, I now there just friends but I don't see why they need to say it.. He was voxing her n they we're talking about sexual things she did to a guy a few days ago , n he voxed back (that's why I love u baby mamma) is it wrong of me to get mad that they talk bout sexual stuff n say I love u?? He wont let me have any contact with any of my exes! Plz let me know if I'm being to harsh or if I'm right!! Ty