I like to think that Satoru and Suguru never actually dated. They'd sneak around and steal kisses here and there but never called it a romantic relationship. I'd say it's because nothing really breaks you like attachments and that's not what jujutsu sorcerers need especially with a job like theirs where you can lose people at any moment.
And I think Satoru didn't see this as a problem with his attachment to Suguru because he's strong and besides, Satoru wouldn't let him die. He didn't think he'd lose Suguru... like that.












