I have a trauma about this couple though this is one of my most favorite couples in Touhou.
there was one comic strip featuring this couple, waking up in Renko's apartment and being generally flirty and fluffy and the atmosphere is all light and lovely, of course there's not even the slightest hint about sadness. Then the view pans out to the front door that apparently has been vandalized with graffiti like "Die Fags!!", "Dyke!" etc.
In hindsight, it's like they give off the aura of giving up their social life and ostracized themselves inside. Or taking to extreme, the first half was actually their ghost after they committed suicide together... (I have such wild imagination that sometimes backfires on myself)