I Am In My Mid 40s. Days After Sex My

I am in my mid 40s. Days after sex my penis head continues to be extremely sensitive and feels almost irritated. Actually, I think the sensation goes through the urethra and hardly ever goes away. Ultimately the penis does not feel right. This started about three years ago and now it is more persistent. A past urologist said it was nothing. I am sure there are no STDs involved since I have been married for over 20 years. There has never been any discharge or burning sensations and I have seen a DR several times since this initially started.