CheesePuff, as a woman who was sexually abused in a similar scenario and during similar years, I can tell you that recovering from abuse like that took me decades of two steps forward, one step back progress.
Even now, I don't know of any truly great resources for recovery, but one that I found useful in the early stages of healing was Amazon.com: The Courage to Heal 4e: A Guide for Women Survivors of Child Sexual Abuse 20th Anniversary Edition (9780061284335): Ellen Bass, Laura Davis: Books
book and its associated workbook Amazon.com: The Courage to Heal Workbook.
At the time I found them (which was when they first got published), they were the most thorough guide on sexual abuse that existed. As I look back now, I can see where they were also limited. I haven't seen the later editions, so this may be improved now, but the limitations to them were that they had a way of making the survivor seem more helpless and advising people to walk on eggshells around them. In early recovery, this extra empathy is good, but it's a very fine line because it can also lead people (like me) to become pretty self-centered.
What I *do* like about it is that it has some excellent exercises that can help a survivor find closure and stop blaming themselves. These are HUGE when it comes to sexual abuse.
Your wife will not be able to heal without finding ways to place responsibility where it belongs - and part of that is on her mother's shoulders. This can be very frightening because it will challenge her beliefs about love and destabilize her entire worldview in the process. She cannot build back up without shattering the beliefs and coping skills she developed over all those years.
She really never had a chance to develop a sense of self. From a very early age, she had to deny major events in her life and pretend they weren't there. She was 'tutored' to believe she was responsible for everyone else's quality of life, that her thoughts, opinions, and beliefs didn't matter or even exist, and that her worth was strictly sexual. She wasn't able to undress in private, talk to her mother privately, or let people know what her life was like. Instinctively, she knew her mother wouldn't protect her because she never had before. She didn't leave the first jerk until he almost killed mom, because your wife didn't have enough value to her mom to prompt action.
You want her to believe that there are good people in the world, but you're possibly the only one she has ever known. She has developed great coping skills for dealing with the crazy ones, but she hasn't had any way of learning what healthy love and trust look like. To her, they're an awful lot like the same vulnerability she's experienced at everyone else's hands.
A good book for partners like you is Allies in Healing: When the Person You Love Was Sexually Abused as a Child
as it helps to answer questions about how to get your own needs met more reliably.
When she says she needs to heal, she is telling you the truth, but it's important to learn how to set boundaries and negotiate agreements.
For me, one of the most important "isms" I developed (and still have) is that if a person doesn't listen to me well, I stop feeling valued by them very easily. It's hard for me to remember that some people just aren't good listeners and it has nothing to do with me. When I met my ex husband, he was an expert at listening and understanding where I was coming from. When we disagreed, he revealed his own views only after he'd shown me he understood my viewpoint completely. That made a HUGE difference for me and let me learn a lot about how to trust and be vulnerable to someone. I never felt like he was trying to force me on things, which allowed me to be receptive to his needs much better.
Best wishes to you both.