If you put energy into genuinely understanding someone, you will understand what their best interests actually are. This allows you to act in their best interests. It also allows you to foresee when there is going to be a conflict between their best interests and your own. This puts you in the position to be able to communicate about it, to problem solve, to caretake and to resolve that conflict of best interests before it turns into something that dissolves the perception of there being love in the relationship.