the girls are all cute but sayu, physically attracted to her or not, is such a presence for him now I can't imagine the others being cool with it emotionally if they want him all in. i'm fairly certain his concern for her will be recurring and certain situations will bring him back to her when his focus should be elsewhere. maybe they'll accept that but it would feel bad. he'd have to date someone completely new.
and he'll absolutely influence her choice in future partners though maybe she could forget him, being at a stage in her life that's about to be incredibly busy and difficult when she meets those familiar faces again.
i do support them as a potential couple and though it lacks the intense drama of him choosing to have sex with her, i think it was important for him to reject her in the narrative here. yes it is important for her to be able to have an experience with someone she loves on her own terms with boundaries she chooses, but it can wait.
she might not be able to be with him and might not meet someone who cares about her quite as much, but i don't really want her tying value in her presence back to sex going forward. it could just be a way to connect as much as possible rather than payment, or maybe both, but i think it's important she heard that she can be held in high regard and remembered without that. it'd be better too for her to start a relationship after resolving as much as she can with her mother, and learning to stand on her own.
honestly while i hope her future is as open as possible it'd be cute if they got to work together and she made proper friends with the others at his company, and met her bestie again.
as for mc yeah maybe he isn't and wont be interested in her physically, or maybe he does need to convince himself bc it's so fundamentally at odds with what he wants for her.
either way i think after some time apart the best way to move forward, couple or no, would be to have each other in their lives again later on, so they aren't worrying. and if they aren't a couple being able to cheer on each other's romances might help them stay secure in not "missing out" on being with the other.