I don't blame her for not going to the inauguration, she despises Trump and why should she be a hypocrite? Jimmy Carter's funeral was more remarkable but maybe that was Trump proximity or I don't know, she was doing something else, or maybe she's just sick of the whole circus.
I'm not going to speculate about their marriage because all of us know the sum total of zero about it and I'm sure it suits certain parts of the Republican party to have these rumours. Perhaps they think it makes the sexual abusing misogynist they have had elected President look better (it doesn't)