https://en.wikipedia.org/wiki/Conspiracy_theory

Plan A: Displacement Through Spousal Exchange
 
While surreptitious non-criminal displacement seems to be the safest way to proceed, this route, or plan, itself comprises several options.  The first and, somewhat paradoxically, certainly the easiest would be to simply take my code-partner’s place in the affections of his spouse.  Once replaced, I would then take over as myself. And, assuming the assets of the spouse are equal to, or exceed, those of my code partner, I would have bettered my circumstances without much ado about anything. But financial betterment is not my primary goal.  Rather, it is just one of several objectives.  Indeed, were financial gain my primary goal, I should suspect there are far easier ways to go about that than the one I am proposing to undertake now.