I would never change anything about myself for someone else. I might change something for myself because I want to make the change.
If you make drastic changes in yourself, then that person is not in love with you - they are in love with the person you are pretending to be. The front you would be putting on could only be maintained for a limited amount of time and when you could no longer maintain that front, he would stray anyway (if he is so inclined).
Be yourself - it works out better for everyone in the long run, especially you.