Welcome to G2G Sue,
There are two fields for dates when entering marriage information:
- Marriage Date:
- Marriage Location:
- Marriage End Date:
You can see those fields clicking on [spouse?] on your own profile and scolling down to the third (3) section.
So you can [add] your mother as the spouse of your father on your father's Edit page, use the WikiTree ID if there's already a profile for your mother, then [edit marriage to your mother's First Name] entering the date your parents got married (Marriage Date), the marriage location and the date they divorced (Marriage End Date).
The Edit Marriage Information page looks different than the one you saw before when clicking [spouse?] on your profile, but the fields are similar.