So it's beyond reason to have a conversation with your loved one about something confided to you from her uncle ?Coping with what, her mother's sexual abuse? MC isn't supposed to know that. Sandra didn't tell MC, she would probably be shocked as all fuck if he came out and said he knew about her mother's sexual abuse.
I think that'd be part of a healthy relationship and would bring them closer together personally but this again is why we don't see eye to eye on the previous issues.
I don't think building walls or being secretive is helping anyone here.