The coldness is more recent than her drinking. The drinking took time before it evolved from recreational to habitual. Also, her mother was an alcoholic.

The coldness came on very suddenly, almost like the flick of a switch.

M46 W48
M11 T14
S11 D8
BD: 2016/05/27
In-home separation: 2016/11/23
Nesting: 2017/06/11
W moves out: 2018/01/07
W goes public with OM: 2018/07/12
I ask for a divorce: 2018/12/14