Someone help please ...

Ladies.. so long story short my fiancé’s cousin is dating my fiancé’s ex gf and I haven’t ever felt good about it. Her being around etc.. well anyways everyday the last like month or so I’ve looked her up on fb and apparently he went through my searches and found thar I’ve been looking her up like 3-4 times a day every day the last few months and now I’m so embarrassed. I knew it was wrong, me and her aren’t even friends on social media.. and now he saw it and I told him it’s not true I don’t look her up and he keeps saying “if you’re telling me you’re not lying then I believe you” but this guilt is killing me .. what do I do.. I know 100% looking her up was wrong but I would always compare myself, her relationship with mine, I’d try and see everything I could about her, I was border line obsessed but I never thought hed be able to see it .. someone please give me advice.. please..