Firstly, why did she have three children with him if is so awful. Secondly, the same applies, if she wants to end the marriage then do the right and honest thing and tell him. No secrets. No going behind his back while pretending all is ok. Tell him and then start the divorce.
I've kept in touch with the now grown daughter of a close friend. I kid you not, she has had 3, count em' 3, children with a meth addict. Why? She wanted all her kids to have the same father. It's something she has always felt very strongly about. She always wanted to be a mother, she wanted a large family, she had an accidental pregnancy, so she kept having kids with a literal tweeker just so they'd all have the same father.
A girl I went to school with had kids with a lying, cheating, chronically unemployed or job hopping, jackass because he promised to change after each birth, never did, but he made beautiful babies.
I have repeatedly been asked why I had a kid at all, much less 2, with my exH. I didn't. Not on purpose, anyway. DD1 was the result of antibiotics interfering with the Pill and no one telling me that was a possibility. Not my pharmacy, not the ER doctor, not my GP. DD#2 was the result of a condom failure.
I know a lot of people with kids who had or have bad relationships. The reason some women keep having kids with men in those relationships are myriad and don't always make sense to other people.
She said it wasn't "black and white"... my translation: yes, I wanted kids, so I put up with you...
I've heard that one in the wild. More than once.
Only if the divorce turns contentious and with the respondents lawyer bringing up the subject matter. Rest assured that the complantants lawyer will definitely not bring it up! The family court judge will not usually bring it up of his own accord, but could certainly be prompted to ask pertinent follow up questions.
In which case, it would be preferable to have a plausible answer prepared, or at least a tacit denial to the assertion that it was being done solely to pad child support from him!
In which case, she had best be prepared to answer any follow up questions to that denial!
I am curious, now. Is this a thing in TX? That's where you live, right? I've been to court for many divorces as moral support, my own divorce, and a few child support cases between unmarried parents. I've never heard anything like this. Usually, it's the judge going over the submitted income and asset documents, the custody agreement or state recommended agreement if they couldn't agree, and setting support based on the state formula. The only time I have ever heard a judge mention conception is when paternity was in question.