The speaker pictures herself as a flower, and falling in love becomes a slow loss of petals. Each time her feelings for the other person deepen, another petal is taken from her. By the end she is "fully revealed," with nothing left to cover what she feels.
The image turns something we usually see as beautiful into something a little painful. Petals protect and decorate a flower, so losing them means losing a kind of shield. The poem seems to say that loving someone made her vulnerable, and that she didn't choose to be exposed so much as have it happen to her. The word "stolen" (the poem's "we're" appears to be a slip for "were") suggests she feels something was taken, not freely given.
The final line, set apart from the rest, lands quietly and with a sense of defeat. The mood is tender, exposed and a bit sad: the feeling of being unable to hide how much someone matters to you. The title's word "feeble" adds to that fragile, powerless tone.