I think we have very good advice already in the topic.
I would just add that there is no true happiness without God. Our first commandment is to love God above all things, and that includes loving Him more than your own wife/husband.
For my own experience I would say that every single time that a couple puts Christ in the center of the marital life, they win. Christ is the infinite source of all love to which you can always go back for, when the love for your spouse fails somehow.
In this sense, it will never be enough to regain your marriage on the basis of “doing nice things” to your wife, like taking her to dinner, talking nice to her, buying her gifts, etc. Your marriage will continue to be unhappy as long as God is not the center of it, for BOTH you and your wife. In your heart, God must stand above your wife. And in her heart it must be then same. When that happens, your marriage will be safe, and you will be happy again.
Don’t force it on her. Invite God to your marriage, and ask her nicely to do the same.
Invite your wife to pray with you. Invite her to go to the mass with you. Invite her to bless the food before lunch and dinner. Invite her to let God get into your marriage, and things will work better.
God bless you and your wife!