Some recent psychological research has addessed this topic. From a simple standpoint the one who is loved: puts forth less effort, spends less money, expends fewer resources, receives more benefits of various types, and has less relationship/partner related mental/emotional turmoil/problems/issues. Thus frm one standpoint it is more beneficial to be loved than to love. However, significant amounts of research exist that describe the benefits of loving someone...mental, emotional, physical, etc.