is the sharing means cucking(netorase) or netorare?
It's a little bit cucking but not quite.
Kat will never cheat on the MC, she loves him totally, she doesn't even do anything when he goes missing for months.
That said, Kat is constantly horny and has a kink to be with other men plus the MC likes to see her getting fucked knowing other men want her but she's totally devoted to him.
She will only ever do anything with your approval and instantly comes back to you the second it's over to be fucked by the one she loves.
I've never shared her personally because she's awesome but plenty of people love that route and from what I hear and see from the pictures folder and scripts it has some great content for people that like it.
I mean like a harem route where you can date all the girls?
No, it isn't. You can have sex with multiple people but you won't be able to be with them. You are given a choice this update of giving up fucking around or giving up his wife.
If you give up the wife it asks you who you want to be with, there is no choice to be with multiple people.