Three's a Crowd. but Four.?

Faith and Sarah are best friends who have known each other their whole lives. Their bond goes beyond love, but their close relationship has made it difficult for them to form bonds with other people, and as such they are incredibly lonely. At first they decide it might be a good idea to share one man, since having separate relationships never seem to work, but when Faith meets her perfect match it could hold more in store for Sarah than she would assume.