Test yourself: one morning over breakfast, look him in the eyes and say "Thank you." He'll naturally look at you in surprise and say "For what?"
Thanks for sticking by me, thanks for your support, thanks for being there when I'm down, thanks for helping me out with ideas when I'm stuck at work, thanks for holding my hand when I'm afraid, thanks for accepting my faults, thanks for not saying anything when I hog the bathroom for three hours, thanks for making me happy, thanks for not teasing me about those few extra pounds, thank you for loving me and thank you for being you!
His smile, teary eyes and trembling lip when you tell him how much you appreciate him will be a great present for you too!