Fiance looking up girls on FB, am I overreacting

I found my fiance 31(M) looking up girls on his search history. It was probably about 12 girls or so. At first he said they were all cousins and family. When I pulled up every one of them, then his story changed to okay we went to high school together. I’ve caught him looking up his ex from high school maybe a year ago and he looked up her husband and her whole family. His excuse was that her mother was a teacher and he was friends with her brother so he wanted to see what they were doing. And he has lied about two other girls that he said were like sisters and I later found out he used to like one of those girls and had a threesome with the other girl but they were like “family”. We have argued about the girls on his fb multiple times and I’ve asked him to block all the girls he ever had a crush on, or if they used to talk or date. And after arguing for about a hour his excuse changed to he went to their accounts to remove them from his friends list, which most of them were unfriended but when I pulled up messages which was from 2011 but he was flirting with them at the time and now looking them up. I don’t know if I’m overreacting. And I’ve never found him cheating, but I’ll find lies like this here and there.