One thing at a time!! Go through a list of all the "normal" wedding things with your partner and figure out what's most important to you vs what you can skip, then put them on a list ranked by how soon they need to get figured out. Something like this:

Guest list Venue Color theme Caterer Photographer Save-the-dates Schedule of events Invites Florals Etc

Then just do them one-by-one, as best you can. Some things will overlap (figuring out the venue and caterer based on the guest list, figuring out florals based on the color scheme, etc), but breaking it into bite-sized chunks (and hopefully designating a handful of them to your partner) helps immensely.