I guess technically by actually doing the story he ruined their relationships first.
Riyo-bunnygirl did that first by recruiting Anastasia to be an enforcer of the Yuri Singularity. There's no indication that Kadoc exists beyond being a character in Gudao's furry yaoi comic. Jury's still out on Xiang Yu though.
Who'd have thought that Osakabe was a lover of vanilla
It's garbage to say the least.He should lose everything he has and be left in tatters.I have nothing left for rent... kukukukuMaster!Lostbelts are scary...It would be more appropriate for him to lose it so spectacularly doing the gacha.It should be impossible for that guy to pull Saber-stolfo.And he realizes that true happiness has been by his side all this time."Wherever You Go, I'll Be There (deep "meaning")"How is this plot?But then Rider-stolfo would notice that he's just using his body for comfort after failing the gacha.You've finally come at last, Saber Astolfo-chan!What a great difference in interpretation.B-but then something like this: I guess Rider Astolfo has always been by my side.It'd also be good to have Rider-stolfo see through this and the distance between the two widen immediately.And thus a dazzling lovey-dovey development ensues.