Suspicious?? *update*

So im gonna start off saying its not very often i have problems with my fiancé and im not usually that jealous girl. So a little back story: theres this girl k that my fiancé used to have a crush on. Fine whatever but when we got together he would still get super excited to see her like too excited so i told him it made me uncomfortable. About a year went by hadn't heard from her til my cousin(they were all friends) brought her to my house. It was fine the first couple times then the 3rd time i ended up leaving for a bit to go to the store and she had messaged my fiancé 12 times and called twice (not exaggerating) trying to get him to go upstairs and he didnt see the messages. She ended up coming over again and just completely ignored me (even my mom had mentioned how weird it was) so it ended up causing some problems between us. So he blocked her. I literally watched him block her. So fast forward i was gone from my house and my fiancé is like can we go to your aunts house (usually like 98% of the time its me asking to go) and im like sure. So i get home make dinner and he just seems excited to get there and im like oh maybe he was just bored all day. So im sitting there and in walks K. So in my head im like that's why he wanted to come here so bad. Well he promised that wasn't why and that he had no idea she was gonna be there so i try to let it go but i had a weird feeling so i went to his messenger. All previous messages are erased and shes unblocked and he swears he didnt do it but im like so facebook just unblocked her?? I guess im just wondering if im crazy or if thats like a red flag??

*Update*

Thank you ladies!! For a second i did think i was overreacting but f**k that my feelings are valid!! Id answer you guys seperately but I'd like to remain anonymous.I almost left but i couldn't see straight so i didn't wanna risk it. He keeps saying he doesn't know how she got unblocked. I asked him if Facebook did it he said no (obviously im not that naive. i know facebook don't do that) i asked so did somebody go on your Facebook and unblock her he said no so then i told him the only possible way for her to be unblocked is for him to do it. He still denies it. Im gonna go into messenger and see if there's a private conversation. I'll update if there is.