We have a situation, where,
2 people, X and Y, love each other selflessly and their happiness lies in the happiness of the other.
In such a case,
The motive for each of the X’s action which may have an influence on Y is Y’s happiness. But X knows (X should know) that Y loves him/her selflessly, so Y’s happiness lies in the happiness of X. Again, X’s happiness is in the happiness of Y and so on.
Now if the action in consideration is such that it has a direct correlation (or negative correlation) with both, ‘Happiness of X’ and ‘Happiness of Y ‘, then a decision can be taken. But if the action is such that it has a direct correlation with one and a negative correlation with the other, a decision can never be taken. Hence, the paradox.
That brings us to the conclusion that a sacrifice can never be made in a mutual selfless love relationship. One will make a sacrifice in case he/she doesn’t know for sure that the other also loves him/her selflessly or that he is proud of his love, in which case, he doesn’t love selflessly.
Then it seems absurd that those who make sacrifices for each other are considered selfless lovers.