Oh really? So if there are so many special single mums that are not irresponsible breeders, why did the one you chose have kid, after kid, after kid, by an irresponsible jerk who was abusive. Wait, don't tell us, she didn't know at first right?
Actually you are right, she was to young to know any better to start with and additionally abused partners can get trapped. Have a chat to a few abused women that have struggled for a number of years and with multiple attempts to leave.
So you're not together anymore? Looks like you were no longer needed after the kids were raised.
You know you may even be correct, but as I can't read minds I'm not sure what her motivations are :)