PS What is the right English idiom to describe an exchange between two equally bad items?

In Russian there is an idiom "to swap an awl for soap", which does not make any sense when translated, but in Russian "awl" and "soap" rhyme and the idiom makes sense.

So basically if you have one bad wife and swap her for another bad wife, there is no gain and you could have just as easily stayed with the original bad wife without incurring the transaction costs of swapping her for the second bad wife.

The reason I am saying is this: had there been a PATTERN of bad relationships in which you'd been riddled with insecurities, then we could have said that the issue is on your side and any new person you choose would repeat pushing your buttons to hurt you, so you might as well stay with this wife and avoid incurring transaction costs of swapping her for somebody else.

It is not the case - you are generally confident. So it is a glitch of this particular relationship which has something to do with this particular wife. That makes it likely that your next wife or gf would be better for you, and you won't be swapping an awl for soap (again, excuse the seemingly nonsensical word expression).