Under their Partners, press What are you trying to fix?, then Something else…, and choose the option saying their partners are in the wrong order. First things first! You can then put them in the right order. For example, if Grandad's second wife shows first, swap them so his first marriage comes first.
Where to find it
Person page (Safe edit on) → under Parents, Partners or Children → What are you trying to fix?
Only people with the "Add people" and "Remove" ticks, with Safe edit on.
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