I agree with you in that I feel that people who have had bad experiences with husbands or aikido teachers or bosses or whatever are responsible to some degree for what has happened - but they are not responsible for ALL of it.
To only focus on the "victim's" responsibility is more or less to absolve the other party of responsibility. There is a difference between failure to set boundaries (your responsibility/fault) and setting clear boundaries and not having them respected (not your fault) - you cannot control and are not responsible for other people's behavior.
People can, if they choose, override your wishes in one way or another, no matter how clearly you state what your boundaries are, and what the consequences will be to you or others.
Sometimes you can either leave, or continue to put up with BS. If you must leave something you have invested in (be it a marriage, or your aikido training/dojo community, or a job), the loss of your marriage, training, or job is NOT necessarily all your fault.
The key it seems to me is information.
Not seeing red flags most people would notice? your fault. Failure to communicate what you need? your fault. Sticking around a lousy situation hoping it will get better all by itself? also your fault. Denying that bad things are happening because you don't want to look at it? your fault.
Not knowing someone's history because they choose to lie about it and nobody has told you otherwise? Not really your fault, unless you believe in hiring private eyes to check everyone out.
Trusting someone because up until point A they have only been pleasant towards you? How can that be your fault?
Forming some kind of agreement or contract with someone, and they don't hold up their end of the bargain? Not your fault.
Someone does something to hurt you, even if you already told them it would? Not your fault, they chose to do it with knowledge of the consequences. It is your fault if this happens over and over and you don't leave.
In some settings, asserting yourself (setting clear boundaries) is not acceptable to the Person In Charge, as it is seen as a threat to their authority. Then you are in the "put up with BS or leave" situation. There are dojos like this. This kind of environment is hard on healthy people and can be dangerous to the aikido student with boundary or past-abuse issues.