A Plum Tree Spirit Troubadour was Urd's first (and, probably, only) boyfriend. Selfish and jealous, he caused many problems and eventually left Urd "to follow his dream". He visited the Morisato Residence once just to accomplish another personal aim (and was baked by Urd's lightning several times). She still has some feelings for him, but it seems to be nostalgia, not love.

source: http://www.world-of-elegance.net/shrine/about-rel.htm