So annoyed

My husband coughs and clears his throat incessantly. I’ve tried having compassion for him, offering him cough drops, hot tea, and other things that might help, but he always says no thank you. His cough and throat clearing are a habit for him and he does it without even realizing it. My thoughts about this are making me so annoyed! I’m actually letting it take away from the joy of spending time with him and sigh constantly and feel so uncomfortable when he does it so much. At night he does it before bed so much that I can’t fall asleep…he does it when we are in the car….before he speaks….ALL THE TIME. I so need help on being cool with this. It’s bothered me for 15 years.