Why should I not constantly drink my own blood out of jealousy, seeing that today my beloved has shared a drink with a rival?

Here, the poet draws a striking and painful contrast between two drinks. While the beloved sits sharing a joyous cup of wine with the rival, the helpless lover is left alone, drinking his own heart's blood in bitter jealousy. 'Drinking one's own blood' is a classic metaphor for suffocating inner agony—the unbearable sting of watching someone else enjoy the intimacy that belongs to your dreams.