We NEVER saw what Ml really want's he ALWAYS adjusted to MC. Every. Single. Time. From the very first moment.
They always did things under his radar, barely the minimum, because HE WAS THAT CONSIDERATE.
He literally said it in the last chapters that MC has no idea what he really wants because they never did it, and then, when they agreed to try it, ML toned it down again UNDER the minimum line. Again.
Even in this very chapter, when the collar came up, he instantly jumped to the very minimal dog-acts, like dog pose and bark, he never mentioned dog treatment, like dogfood, pi**, etc, no, he literally asked about the very, very vanilla part of dog-plays, and MC already backed up to just wear a collar, and nothing else..
He stucked at the symbolism.
...which is fine, i mean, not everybody is a hardore mazochis, of course - but its a waaaay smaller step that ML's steps, who literally had to drop the WHOLE ROLEPLAY and stuck on the symbolism level too. Like it would be enough for him...
It's ML who really adjusted all along. Really.
The only reason I would never say MC should take more step to make things fair is because we're talking about BDSM here, not a normal relationship. which means there's NO ROOM for debates and compromises. If you don't want something, that's ALWAYS valid, you DON'T need to negotiate. That's the first role of BDSM.