Click on the EDIT tab on the profile, once in the Edit Mode, look on the right of the screen, find EDIT FAMILY, look downt the colimn to find Spouses, find - add/remove a spouse. Click on that, and either enter the new person or insert their WikiTree ID in the appropriate box.
I just looked at Franiszek's profile, it looks like you've got the spouses and children sorted out.
Good work