GPS Coordinates on my contact card

Hi my hubby has a iPhone 12 Pro Max, and I noticed map coordinates on my hubbys contact card under is second work address area. I clicked on it and it took me to a map with his name and a star on a house. He has no idea how it got there sadly. Can this just happen automatically or an update glitch. I know significant locations won’t allow me to see anymore since all the updates. Will Siri add in a map coordinates on her own as a suggestion or will this only happen if he frequents that address a lot? His actual work is 10 mins away from that address. Could it just have been added by mistake or is he flat out cheating. How does a name even show up on a house? I got my house as a favorite on mine and it has never showed my name on my house. Please help me sort this out in my head. Thank you and I’m super embarrassed but super bad at technology. I wish I could check his significant locations but it won’t let me.