How do I leave my husband

Recently I found my husband still watching porn after I already asked him not to.. then after that I found him on dating sites telling girls they are beautiful calling them baby and talking sexually.. he even met one of them.. I talked to her and she said they didn’t do anything but talk.. and if she knew he was married she wouldn’t have talked to him......once he saw that I knew he cried and begged me to stay and said he would never do it again he unlocked his phone and turned on his location for me to see at all times a week later the location turned off and he’s asking how long do u need it 😑 and everything is just back to normal like nothing happened for him meanwhile I’m heartbroken how can you move on so quickly I just can’t take him acting like nothing happened and now giving me Ayyyeee have a 7 years old and a 2 month old.. he did it all while I was pregnant

I should mention that I don’t think he is doing anything anymore he’s not on his phone anymore and we are always together.. but it’s hard for me to move on so quickly