You do not need to give any other explanation other than I am sorry this is not working anymore it is over. Then work at disentangling your finances.
No reason to give any explanation beyond that. She is going to take anyexplanation as a personal attack or challenge.
Stop dragging things out and end your relationship like ripping off a stuck bandage. Yes it hurts like a son of a Bitch for a bit but hurts a lot less than taking it off slowly.
40 yo straight female
Married in the eyes of the government to Butch since 2001...
Murf my monogamous second husband has been with me since May of 2012.
In a V relationship with an average 60/40 split of time. Only due to Murf's and Butch's crappy work schedules.