Tom and Holly, thank you both for answering my question.
It works differently here from MyHeritage website, so I guess i have to get used to and adapt to this fact.
The difference is, when i clear the Current Last Name, it refills with the word "Anonymous". In MyHeritage, clearing the Current Last Name is perfectly fine, it is not refilled by anything and the woman is then showed as if Current Last Name had indeed her husbands last name in it.
So when this person was attached to Mr. Wrong, and i reconnect her to Mr. Right, in MyHeritage i do not have to change her Current Last Name, simply because it is empty. I now understand that this behaviour is specific for MyHeritage and not for WikiTree.