Ughh confusing poem, need help understanding?

Maybe I got my mind conditioned to ism from watching too much TV, but it's all I can come up with; the poem's about a woman in love with another woman who is in love with a man. The speaker sees her by candlelight, with her man on a terrace, a man that is not convinced about the other woman's love. The speaker is jealous, and as she approaches her with the candle, her beloved scorches her finger in the flame to show how much the speaker causes her pain. It's done deliberately and intuitively as a way to defeat the love of the speaker (Cupid's aim). The speaker then doesn't think the beloved knows herself, that she is a , but tells her to never mind her grieving heart, as it comes from other affairs better left unseen. The speaker tells her she tries to forget their nights, the old gray wrinkles in her brain, but she still cannot forget.