I think most women poison those we love on at least some occasions in our lives...although, unlike poor Lord Randal, our victims tend to be symbolically poisoned rather than literally. Poison is called a woman's weapon, and there might a good reason for this.
When someone whom we love hurts us, we may react with a deep, aching hurt that instead of bursting forth in rage remains within us, slowly consuming us, until the anger we feel toward the other person literally poisons our view of him (or her). We smear their image with blackness until nothing redeemable appears to remain...and certainly nothing worth loving any longer.
I did this to my ex-husband. He had an affair with a former girlfriend a few years into our marriage, and instead of immediately breaking up with him, which would have been the really kind thing to do for both of us, I remained with him a year. During that year, my anger toward him steadily eroded any feeling of love or compassion I might have retained for him. Every time we argued, my anger would come spilling out, not in a rage but in a cold, calculated, vicious anger that left him speechless and only fed on the hatred that was inside me. By the time I finally divorced him, and dumped him at his mother's house, where he planned to stay briefly, I was almost laughing as I drove away and left him in tears. I had gone from being someone who would have done anything for him to someone who would have done almost anything to him, just to see him suffer.
We can only conjecture on why Lord Randal's lover poisoned him, but it certainly makes one wonder whether he wounded her in some way that poisoned her feelings toward him, leading her to betray him in the ultimate manner.
