i would be up for filling that if you think she would fit! did you have any preference for when the relationship would have occurred? blair came out in 2012 and has become known since then for making lots of stupid and dramatic decisions with her relationships so moving really fast initially would be par for the course with her, and this might have been the one time people thought she was getting her act together only for it to not work out in the end? she tends to not have great relationships with her exes because she usually ends things in an abrupt and/or terrible way, but i could see things being different for her after being in a serious relationship with someone for a long stretch of time, so if you wanted to say it came to a natural end and they kept things mellow, that would work!