Enabling the non-thanker
Short and sweet is better than none at all.
We all have one in the family. Spouse. Child. Mostly spouse. Someone who puts off writing thank you note cards until it’s embarrassingly late. Eventually you're forced to pick up the slack.
Here’s the thing – for the most part, your husband probably doesn’t want to use your floral/teddy bear/cute babies cards. Nothing personal and nothing against your cards – he’s just not comfortable using them.
So make it easier on both of you and have appropriate custom stationery for everyone in the household. Perhaps a classic notecard with last name feels right. Choose a simple, non-script font for personalization and keep colors neutral. Most importantly, make sure he knows where the stationary/stationery is stored. Apparently “I don’t know where you keep anything” is universal.