You Better Do Something For Valentines Day
I don't care that you and your mate have an "agreement", sooner or later you will be called on the carpet for not celebrating Valentines Day.
The problem with trying to not celebrate Valentines is that other people do. Your other will see the flowers being delivered, the candy heart on the desk and at the very least hear the stories of romantic weekends and visits to local restaurants.
So do something even if it's sweet and small. Sweet and small will always be appreciated and may keep you from having to engage in some grand gesture in the future. Even if your mate says "no Valentines", see if you can switch that to a $5 or less treat. You can agree to exchange cards or one can prepare dinner for the other.
I am not sure of many things. In fact, as I get older I'm sure of less than ever before. I am positive however that if you don't engage in some type of Valentines sentiment, it will come back and bite you in the ass (and not in a good way).