A cloud of confusion passed over Tuor's face as he listened to her words. Stop loving her? He was not capable of such a thing. That he knew, though he lacked the wisdom of her kind.
"Men are able to, yes," he said, not wanting to lie to her. "But many do not. Beren never fell out of love with Lúthien. My mother and father. Húrin and Morwen. There are as many Men who love for life as there are those who don't. Why do you assume I will be one of the bad ones?"
He found himself a little hurt that she obviously had so little faith in their love, that she thought that he would be one of those fickle men who committed their heart to someone, then changed their mind a few years down the line.