This is a happy ending story about 17×28 Natsugo and their failed wedding night, followed by a lovey-dovey sex. A longer sample is available on pixiv.

Although they’re dating, Suguru is still a student, so
they’ve made a promise not to go beyond kissing. Satoru has also told them
that they won’t have sex until Suguru graduates, and that
if they break that promise, they’ll break up.

Because of this, Suguru is constantly being brought to the brink, sulking. Meanwhile, Satoru is also holding back , almost making a move
on Suguru , and using toys to comfort himself. Just then, when Suguru finds out that Satoru has been proposed to, he suspects that Satoru is using his student status as an excuse to toy with him, and tries to force himself on him…!? The newest release from the circle [Rays] in the “Tickling Emotions JB2024” series is a five-volume [Jujutsu Kaisen ] summer story about a student (17) and a teacher (28) set in a peaceful world where everyone is still alive. They miss each other and their wedding night ends in a failed one, but they still end up having a sweet, loving sex. Enjoy the happy ending story, “MY DARLING,” in your hands! ♡