It is harder for men to open up than it is for women. Perhaps you're thinking she'll think of you as weak or less of a man if you do but that is not true. Women need verbal assurances of continuing love, along with frequent acts of tenderness from the person they are with, this shows a personal interest that would help to promote a truly satisfying marriage for the both of you because your wife will feel loved and appreciated if you open up your heart and confide in her, that is what every woman wants, to feel like she matters and is the most important thing in a man's life. Your wife feels lonely because you hold back. Vocalizing your personal feelings in a frank and winning manner will do much more to improve your marriage than does remaining silent and sullen. I can understand why you feel the way you do and why you guard you heart because I've done it too, but you have to have the courage to let down your walls and embrace that vulnerability that comes with being in love.

I wish you both the best.