The funny thing is that it is quite possible to mark a person as "partner", but in the statistics, for one thing, he/she still turns up as husband/wife! Guess this program is intended for people with less free outlook on the subject of marriage ...
Currently, we don't support these kind of relationships.
Nonetheless, we are working on an exciting new version of the online tree that will allow you to add / show partners and other complex relationships.
I am sorry for the inconvenience.
Naty / MyHeritage Support Team