Philosophical argument for the Trinity from God's essential love

One of God's essential attributes is love. Selfless love is greater than selfish (self-directed) love. But a strictly unitarian God (like the God of Islam) had no one to love before creation — making God either dependent on creation for the expression of his essential nature, or not essentially loving until creation. Both options are incompatible with classical theism. This suggests God is multi-personal. Why three persons specifically? Richard Swinburne ("Was Jesus God?") argues: introducing a third divine person introduces the new quality of cooperation and shared love — a love that extends beyond self and other to a third party. Introducing a fourth person adds no new quality of goodness. Three therefore becomes the number that maximizes divine love without redundancy. This provides a philosophical basis for the Trinity from first principles.