weird your therapist thinks it is not you and it is them? That is really weird. Does this therapist think every single older lady you wanted to be like your mother was at fault being older lady coming close to your life's path? Wow!
I think at least reading your post there are two sort of related issues:
One is your husband is not helpful to nurture this relationship. and this probably creates the atmosphere you find yourself.
The second issue your unresolved mother issues (which you acknowledged) but you are not willing or you are not given opportunity to go deep into this to resolve and process in therapy.
I do not know the solution but if I was in your shoes: after 5 yrs of marriage and having in-laws who do not care, I would let them go. I would be super polite, respectful and even go as much as to imagine how much my neediness is destroying any chance but I would move on. Sometimes if when we let go things, they come back to us.
The second issue is something you should challenge your therapy to go deeper. It sounds core issues and unless it is resolved psychologically, you will keep repeating and it will get bigger and bigger because it involves force desire to have another person to give you love which obviously is not for anyone to demand.
Good luck