This fight seemed to be one that'd continue for days.
"I'm not going to let you get yourself killed."
You were beginning to sound like Nighteye, and it was frustrating to Toshinori; how was he supposed to keep you safe if you wouldn't let him? Injuries were just injuries, until he was dead, he would have to keep pushing through. As the number one hero his duties were clear and he not only provided protection but hope, and in the case of villains, fear. His job was important.
"Stop doing this!"
He had tried to block out the things you said to him, tried to ignore the sense behind the words and the desperate tears that gathered at the corner of your eyes. He tried, and tried, and tried, and soon it became easy. But it never became easier for you to watch him kill himself, as you liked to say. And soon you couldn't bear to watch him do it.
"..."
That's all he heard from you now, complete silence. He had successfully pushed you away as he had hoped, but he had done nothing to quiet your worries. You were important but so was his duty. To just give that all up... The more he looks back on it, the more he realizes how selfish he was; he had sacrificed not just his health but his good friendship with Nighteye, and his relationship with you.
In the end he wonders if things could have gone differently, but he's learnt long ago that there's no point dwelling on the past.