It seems like your reasons to NOT un-friend are actually good reasons TO un-friend. Evidence can be gathered during discovery if you choose to D in an adversarial manner: It won't do you much (any) good to see it as it happens. Also, how can you prevent her from changing her relationship status? The rest of the world will have their thoughts. You should be letting go of yours.
Alternatively, you can put her into a different group, such as "Acquaintances" or "Restricted", which will sandbox her from your normal view. That would require willpower to not look, but would keep the avenue open.
Me: 30, W: 29 S: 4 T: 14 M: 5 BD: March, 2015, ILYBNILWY, IDLY, Need Space OM, EA/PA Discovered (drunken kissing, she says she stopped there? NOPE!): March 2015 S: April 25th, 2015
