I'm struggling with this question myself.  I will say once you find resources like Our Path and SSN, and you find out you aren't alone in your experiences, you start to have the painful realization that yes, at a minimum we are all victims of integrity abuse.  Right now for me because I'm a SAHM, I am slowly starting to realize that I'm very likely being financially abused.  While I'm not being denied my basic needs, finances are being used to manipulate me and prevent me from having the space and mental wellness that space provides. The impetus for this manipulation at it's core is my son.  Basically if you get the space and care you feel you need I won't be able to maintain the level of expenditure on our child.  Therefore he will suffer for our separation.  This is an odd concept because my transitioning husband spends very little time at home, but won't take the initiative to get his own place either.  I'm always of mixed feelings because I know my son needs his dad around too.  It's all manipulative and therefore feels abusive.

Hailyourself,

 I don't mean to be mean, but the last thing your son needs to be around is his father while he's transitioning. (Or after.) 

What you son needs--what all children need--is stability and consistency.  And a parent who is transitioning is unable to provide that.  Your son does not need a father who is constantly shifting his appearance, and is so caught up in his own transition that he has little care or attention to give your son.  (Or worse, who starts asking your son to call him "Mom.")  It is confusing and painful for a child to have to deny the reality he sees with his own eyes.  

It's not all that surprising that your husband won't take the initiative to leave, either; all a transitioning person's energy is spent on themselves, and they don't see why they should spend any time or effort thinking about others. 

straightwifeinNZ wrote:

How did I find myself in this position where I put up with this treatment for so long?
And how can I avoid it happening again in future relationships?

Such a challenging journey to have to walk.

I have asked myself that question a thousand times. After much reflection, the answer is: because I cared and loved fully and unconditionally. I loved someone who never actually loved me and used me for 23 years. That said, you have to forgive yourself and learn the hard lessons. I discovered the red flags were there from day 1. I ignored, didnt know what to do, or simply justified her behavior and treatment of me "for the sake of the relationship". The hard lesson? Never do anything for the sake of the relationship. Do it for you. When you find someone who takes care and loves themselves, so they can love you, and you love yourself so you can love them, that is where the magic happens. 
I reconnected with a HS friend. Hadn't spoken in 25 years. She has gone through similar. Now we have been together for several months and it has shown me for the first time in my life, what a real relationship looks like and feels like. My marriage was awful, but if you find my original post here I described it as "great". I didn't know what I didn't know. Now I do. You will too in time. But you have to be very self reflective and be willing to go VERY deep to ask "why did I feel ok with being treated as less than? The root cause identification and resolution will set you free.