Spoilers obviously… 
So I’m nearing the end and was romancing Tom (even through the bugger’s alcoholism and general grumpy bastardness) and got the ‘betrayal scene’ where you discover he’s been trying to kill you.
Does this happen even if he’s at full relationship with you? I was only at 60 something relationship with him despite him being my boyfriend, but wasn’t sure if you could convince him out of it if you were at 100 or whatever? Although I suspect it’s a scripted event to ‘push’ you out of the Cathedral.
Thanks!