I don't think he should withhold any of his feelings on account of her reactions at all. Be careful how he states them, perhaps. Withhold or sugar-coat, no. His feelings are what they are, not something he's consciously manufactured. The way she handles his feelings is not his responsibility, it is her problem to deal with. As long as he is withholding those feelings, there is going to be a level of mistrust and the relationship isn't going to move forward. By putting his feelings out there, in a loving way mind you, and not rescuing her from them he forces her into growing as well.
