You both need to set limits with the daughter and keep them, and make some protected time for yourselves.
It won’t take much: he can still spend a lot of time with daughter, so long as he grows a spine and tells her no when that is the right thing to do, and so long as he stops neglecting you and the health of your mutual relationship.
Have you ever gotten sucked into something that you were also ashamed to read? I was listlessly checking my email when I noticed a text ad that I must have seen more than 10,000 times. The worst mistake a woman can make is not seeking help.
When a child is allowed to split the marriage, the partners suffer, as you well know from your own experience.It is as though a fence or boundary has been drawn around the adults which functions to keep their secrets inside and to unify them in front of their children.It’s not so much that having this idealized boundary around the adults in a household is so great in of itself.You both should be ready for daughter to throw fits and perhaps even move out (if she can).This is all normal, and will tend to subside once it becomes clear that the new limits you both set are not something she can manipulate.