How old weere they when they got married?

I'm not sure. But in Gyuha's father's birthday party, when his father offered him to set up a marriage meeting for Gyuha, his father did say, "Thirty is right around the corner.."

Great thank you! I j6st started rereading and found out Chayoung is 30 when they started doing the deed, so i thinj his amnesia is 2 years before the beginning of the relationship