No. What you just commented was a bad faith argument. Never did I say they were on the same level, and you know it.
They however are both about taking advantage of people and are both kinks. It's the same principle. Ayane isn't choosing some random mattress, she's choosing her friend's and she knows it'd hurt them if they ever found out. One being worse doesn't mean they both aren't wrong. It's not like Ayane hasn't forced herself on Ami as well. Possibly stealing her first kiss.
Also "mostly a fantasy" isn't a fantasy, no matter how you word it. She's defiling the possessions of her friends and betraying their trust, simply because it makes her feel good while knowing it'd hurt them if they found out.
If Ami knew he would be happy, she would give her blessing. Everything she's done is about making him happy. Her love is overprotective, but it's not that possessive. She's mentioned more than once she's willing to share, and even recently implied she'd raise his and Ayane's baby. You seem to just want Ami to be evil at this point, tbh.