Can therapy save my marriage?

The short answer is: no
But it may help you and your partner save it if you want to. In marriage counseling we try to determine who is responsible for what and we try to offer tools to learn how to respect, negotiate, and, above all, allow each member of the family to grow without doing it at the cost of the other members of the family. Sustainability , love and trust are the elements of great human relationships.
In most cases there is a limited amount of sessions for the couple. When each member is conscious how their changes can improve the partnership, they work on them individually and then there are sessions to adjust the improvements.