Responses
Hes not suspicious Masa is doing it w other doms, he's unconsciously jealous
They both used to have a multiple fuckbuddies lifestyle. Oto is conflicted bc they both engaged in it as a need, which is why he thinks he shouldn't say anything to Masa
At the party it was a moment of realization for him, that Masa COULD play with both dynamics. I'd compare it to dating a bisexual for the first time and realizing you can get jealous of both men and women

"Masa night not be limiting himself to subs" but he's said he's letting out his dom urges which you're suspicious of but why are you now thinking he's doing stuff with doms so sub stuff dwhen he said it's only you cause if he could do dom stuff to another dom he'd do it to you there's literally no reason to suspect that he's with other doms did I miss something