I don’t know what to do

My boyfriend has a baby mum and he has two kids with her... he has promised in the past that he finished with her and only ‘told her’ he was seeing someone around two weeks ago. We have been together 4 months. I have gone through his phone 2 times, i know... but i always found him flirting to other girls and his baby mom. Just last night i looked at it again and he is telling some girl from his uni that he liked her and wanted to have a face to face conversation. He also still calls his baby mum babe and keeps the pictures of her in his phone. At the same time, he is quite sweet and caring and i have gotten really attatched to him. But i can’t keep feeling like shit because of this

Any suggestions ????