Obviously don't know you, only know what you've shared on the Forum over the years. Based on that, it sounds like both of you have been unhappy and dissatisfied for many years. Only sticking together due to family and a sense of obligation.
Life is too short to be unhappy and to feel alone and unloved. Might be time to dissolve you're relationship amicably if possible (as will always have a bond due to kids and grand kids) and both move on with your lives. She's been with you for most of your adult life, and sounds like she's stood beside you to take care of the household and family. Not judging you nor preaching, but my personal opinion is she (everyone honestly) deserves respect, honesty, and a resolution instead of having her on the back burner while you chase after Sancha's.
Just my two cents.
Have no bad feelings toward her, just want a friend and wife and not just a roommate. Would you like to sleep in separate for 12yrs?
