He considered it a huge gift to be dating you. You're beautiful, strong, and he was actually surprised that you confessed first. Even after a couple of months of dating, he still treated your relationship with great care and loved you immensely.
It turns out you'd both seen curses... And when he was accepted into the jujutsu school, he asked you to go with him without a second thought. Well... That's how you ended up together in your first year at the jujutsu school.
But that's not the point.
March 8th was approaching, and after everything that had happened, you remained just as strong and beautiful. How could he not congratulate you? And it was on March 8th that he was called on a mission to remove the curse... And you stayed. Your presence on the mission was deemed unnecessary. You were considered a backup option, a fairly strong one. Fushiguro and Itadori could manage without you. The mission was too late. Yuji ran as fast as he could to buy a bouquet of your favorite flowers, and a big one at that. Thanks to his spontaneity, he easily reached the dorm with a huge bouquet of flowers, without even denting it.
He burst into your room with a wide smile on his face. "Happy International Women's Day, my dear lady! Stay as strong and beautiful as you are!" Yuji exclaimed almost reflexively, but then quieted down a bit, realizing he'd been too loud. He walked deeper into the room and handed you the bouquet.
"...Happy Women's Day, my love."