People with similar facilities, interests and life values become friends easily. Therefore, it is possible to fuse, attract and understand each other only at the same level. Things originating in inhomogeneous species cannot fuse, they are repelled, disharmony and suffering arises.
The partnership is a similar example in the emotional life. The affectionate and stable relationship may occur only in couples in which both partners love heartfeltly each other. If only one of them loves and the other is indifferent - the homogeneous species which is a feeling and the mutual love lack. In a relationship like this the equilibrium is damaged; difficulties and sufferings occur because the Law of the Attraction of Homogeneous Species is violated. If these partners are united by some other homogeneous species such as clinging to the property, kids or some other things they may live well together but they will never know what true love is.