You cannot build a relationship that already exists. "Fixing" or "rebuilding" the relationship is how you want to create a stronger relationship. Yes, you can always rebuild a relationship but it is never easy. First, you must take into account what is harming the relationship. This could be anything from the loss of a family member, arguments, miscommunication, etc. More likely, there are numerous pieces harming this relationship so it might be best to make a list. Second, review your list. What can we do about each point? Therapy for the loss of a family member? Coping strategies? Anger management? Self-reflection? A method for how to handle arguments is almost always beneficial. Is one of the participants in the relationship an introvert? Do they need reflection time for a topic to provide full communication to get their thoughts across? Etc. Some couples cannot do this alone and so it is a good idea to visit a counseling center near you. If you are short of funds, search for a counseling master's program at a university near you. They often offer discount, or even free, counseling to the community as their students need a certain number of hours with clients.