There could be a couple of different reasons why your husband would not purchase you flowers or gifts the whole 15 years. Some guys are not into giving flowers or gifts even though they appreicate you. Some just do not think that it really matters.
Because he doesn't speak your love language! Sit down and go over the 5 love laungages with him and express to him that your live languages are the way you feel and recurve love. Maybe than he will understand how important it is to you.
It's just not important to him. You can be upset when he fails you in the romance department. I prefer to remember all those other days when he's the best guy in the world. Let your disappointment go cause you can't change it.