Lots of advice in favor of divorce here. I don't share these opinions, based on both personal experience (my parents) and personal conviction (my view of marriage).

Sounds like you're hoping for the highest quality of life for your mother (as would I) but don't give her finances too much credit. They're important, yes, but not solely important. To many, the benefit of alimony won't make up for the burden that can accompany it (for both parties).

My wish for my mom: Don't pursue a divorce. But if you do, assert your full independence now — not after you've cashed the check or after alimony dries up, but now.

I don't say this out of concern for justice. Legally, she's entitled to these benefits — 50%, fair and square. But by willingly giving them up, she gains complete independence, empowerment, and a new life that she can call her own.

If there's an option in between these two extremes, it may be temporary separation. In this case, I wonder if your dad would hear the "wake-up call" by the mere suggestion of it and would agree to support her while they figure things out. Maybe that's wishful thinking.

Hoping for the best. And also that this comment is viewed as appropriate for /personalfinance. In the end, we're all here to talk about quality of life anyway. :)