Need to vent and possible advise

So I went through my SO phone and I don't usually do that but I had a gut feeling about something and I was always told to go with my gut and sure enough I ask and he lies to my face so I give it a couple of days and I check again and he's still lying to my face. He's been telling me he don't love anyone else but me and all these other girls don't matter and yada yada but he's looking up pages of girls to masturbate to and idc if he gets off on his own but not while looking at other girls. So I confront him and told him I didn't trust him and he's like "we'll would you rather me cheat on you or just masturbate?" If you really love someone you don't need to be looking at other girls to get off when I'm not around right?! I'm just trying to keep myself calm cuz I'm 16w4d with our child and I don't want to stress myself out over his petty shit! How would you ladies feel or what would you say or do in a situation like this?! No rude comments or anything about well he's a guy, fuk that bull!