How I told him

Well, he pretty much knew it, but I wanted to make it different, so I bought a little baby outfit and a card.

I put the outfit inside my purse and we met for sushi after his work. Later I asked him to grab something inside my purse and he took out the outfit, looked at me and asked: "who is this for?", he knew it!

So I gave him the card.

It wasn't a huge surprise as he was pretty sure of it already.

I researched and found out that the baby should be smaller than a little grain of rice.