I totally agree with you. Yes, it is a surprise, but on the other hand, it makes total sense. From culture perspective, I think people are usually get marry around that age in Asia. The people around you will start to remind you "marriage" around that age. Also in the past 3 years, he is back to his hometown, his family, and his familiar environment. It seems a perfect time to start a new(or deeper an existing) relationship. He is at right age, right? He just chose to announce it till the marriage. Nothing wrong with that.