Excellent question, one of the most difficult to reconcile when a marriage ends. This comes up often with spouses who are religious and regard the vow not just to each other but to God, family, and friends. It can leave one feeling guilty and ashamed of not being able to keep the promise.
The question I present to spouses struggling with this is, "Was it your choice to leave the marriage?" If not, allow yourself to let go of some of the guilt and shame about breaking the vow, especially if it was not what you wanted. A vow takes two; if your wife chose to break hers, you are relieved on your end. In time, you can grieve the end of your marriage vow, heal from the hurt, and open your heart to the possibility of making another promise to love with God's blessing.