He's expressly told you that he doesn't love you.
He's openly contacting other women and buying them sex toys.
He's changed his WhattsApp/Insta etc to block you from seeing anything.
He's told you that he is actively seeking other women to sleep with.
He's told you the 'role' you are now expected to play, i.e 'Mother' and 'facilitator' of/for his 'life'. i.e You're good enough to go on holiday with him and the kids, but only so he can holiday with zero 'expectations' of parenting/help/support from him (and most likely so he can leave you alone in the evenings with the kids, and he can fuck off drinking and womanizing till the dawn).
So I'm confused, what is it exactly that you deem 'worth saving' exactly?
He is simply using you. He has zero interest in you.
Are you happy to show your DC this 'shining example' of a 'marriage'? Where the needs of one are all important, and the needs of you and the DC aren't even considered, much less 'respected' or even 'considered' ffs.
His selfishness is total and all encompassing, so are you happy for the rest of the family to 'accommodate' the abusive prick? Or not?