Elena was in relationship with Shuichi but did not do something "dirty", she wiped both of their memories and now Elena cuck herself knowing they're in relationship...
K...
Well, she is sacrificing her not being with Shuichi so he and Claire can be happy without some painful memories Elena wiped... hurting herself so he can be happy...
Seems like Claire corrupted Shuichi, he doesn't react intimidated by her kinky personality and actually felt sad he didn't do anything with Elena.
Our boy becoming a man, finally.