When he changes my name

On his phone .. kind of suspicious so I called him while we were in bed instead of doing our alarm to wake up and I glanced at his phone Th first thing that comes up is not what he had me under a couple weeks ago which is baby love but Instead it’s “baby (my sons name)” I asked him why he put our sons name and changed it he said bc it says baby for me and my sons name for him I’m like ??? That’s so stupid and he says bc he feels happy to see it’s his son calling etc. ridiculous my son is 1 he doesn’t even talk or call him

He does have a history of lying and cheating bcs he goes back and forth between me and his ex. I’m thinking he changed it incsss his ex sees his phone or if I call while one of their kids are playing with the phone ..

Should I be mad? Or am I over reacting

I just asked him again and he got annoyed that I kept asking and that I was even upset about it but I’m upset bc it seems like he was changing it because of her Incase she saw it under baby love & wonder who is baby love

He said pls understand it’s just bc he loves to see his sons name pop up when we video call or send pics or whatever I’m just like this is ridiculous but part of me believes him and thinks I’m ridiculous for even thinking this way but jst don’t know why he even went to all th trouble of changing it in the first place. I don’t even have energy to delete or block random numbers or save ppls numbers so idk