Don't be so sure, that is one reason why her first marriage failed, Murphy isn't cut out for domestication.
The text told us everything we need to know about why Murphy 2 previous marriges fail.
Her first husband, Greg if I remember correctly, suffers from cancer and choose to leave Murphy because he don't want to burden her. From the pictures shown in book 4, those 2 are childhood sweethearts.
According to Murphy, her second husband wanted her to stay at home because he can't handle Murphy having a better career in the police force. From what he did in book 6 by marrying Murphy's sister and Mama Murphy's reaction, what Murphy say has quite some credibility.
From what I see, her 2 previous marriges fail because both of her exs is not strong enough to handle her. Murphy is too compotent, and becoming the spouse of such a woman is never easy for your average man. The same reason why a successful and rich career woman tends to have a hard time finding a husband in real life. The problem is not on the woman, it is on the man. It is easy for a strong man to marry a weak woman, but vice versa?
difficult, difficult, difficult!!!
Why do you think Mama Murphy look so highly upon Harry once she saw he is able to win an arguement against Murphy? Mama Murphy must have seen a potential son in law right there.