every silver lining eh? 
It is sad, I know exactly what you mean, the what ifs, the doubts, the memories of hopes that never manifested.
In Why Does He Do That, we are shown conclusively that WE are not to blame.
IMO, Abuse is nothing to do with gender, it is everything to do with control.
I wonder, could you call WA or Rainbow and ask them if there is a good book to help you as much as Why Does He Do That can. I feel that even though the gender is irrelevant, for words to truly resonate with you, they really have to be pertinent to your situation.
It's My Life Now, by Meg Kennedy Duggan has a whole chapter devoted to abuse in same sex relationships, but this is a book for those that are out, I feel it may be beneficial though, if it explains the dynamics of abuse, but have not read it myself. From the 'look inside' function, it would appear that the greater subject of abuse is discussed, but to what extent I don't know.
I want you to find a way of understanding that you didn't do this, that this is something being done TO you, that you should have no shame. Sure you will feel sad, but I don't want you turning this in on yourself, that would be grossly unfair on you.