I can't bring myself to hate or despise Tsukishima. I feel like he actually does have his heart in the right place. Is he selfish? Yes, to some extent, but every other character is also and their scheming and backstabbing are far worse than anything he's done. On his end, it is merely inaction and he genuinely loves Yukita, as she loves him, though she lacks the memories of whatever happened before.
In this end, the dude from the last few chapters really did commit multiple crimes and tried to tear them apart without her consent by back-handed methods and indicated he'd be willing to rape her if it meant she got her memories back. The morality of what he's doing is far, far worse by his "by any means necessary" approach. Worse, instead of trying to convince her with the truth, he pulls underhanded tactics to achieve victory and force her into marriage.
Quite the situation tbh.