It’s tricky, because the dates are sort of spread out, and we don’t know what their life was like.

My sister separated from her husband a few years ago. They’re still on good terms. They’re great friends, in fact, and each other’s closest confidant. I don’t think either actually want to divorce or ‘move on’ - She’s in her early 50’s, and he’s in his mid 60’s. They now live separately but have dinner together at least once a week, sometimes more. They do cook for each other, too.

Anyway - the dates for the poisonings are several months apart -

• November 2021 - Tupperware of pasta
• May 2022 - Curry during shared camping trip (The one that nearly killed him)
• September 2022 - Vegetable wrap during a vacation together
• February 2023 - He’s already suspicious and did not eat a batch of cookies that were left for him
• June 2023 - He skipped out on the meal that killed his parents and aunt, after warning his dad. (He assumed they would be fine.)

I could see if they were still taking vacations and going on trips that were friendly, perhaps he really didn’t suspect her. Or, perhaps more darkly, (and purely speculatively) either she didn’t want to let go of him, or he refused to divorce her or leave her life.
We just do not have a clear picture of their dynamic based on this article, which tells the facts given in the trial, as well as some information regarding evidence not admitted about her efforts to poison him, but offers no information about their reasons for splitting, or social life after the split.
Wondering heavily if perhaps there’s some unknowns here that would have altered the prosecutions case, had motives for the wife trying to poison the husband been established.