"Of course I want my wife to be happy again but if I’m being truthful, my friend is very dear to me and she is part of my life now too."
Said every man who is emotionally enmeshed with a woman friend, ever.
None of my colleagues or work friends have ever become so dear that I would put their feelings above my husband's. If you've become so attached that you don't want to give up your friend, take a harder look at the relationship. Is she becoming the person you confide in? Do you go with her for lunch or breaks, just you two? Meet up or take walks? Things can get out-of-hand so easily. People end up getting attached in ways they didn't expect. Partners can be hurt, and marriages break down.
When you married, you took vows to love, honor, and cherish your wife. You promised to put her first; to forsake all others. Can you not see that you're putting this woman in the place where your life partner should be? Giving her time and energy that you should be spending on your wife? Oh, and do you exchange gifts with your friend?
Faithfulness means more than having no physical relationship. Are you emotionally faithful, too, or have you put your friend in the middle of your marriage?
If you love your wife, don't cultivate friendships where you become so attached to other women that you make them part of your life!
It really is that simple.