There's no telling when Leviathan will open back up unfortunately, so somebody will end having to move regardless somehow (either you going to their Primal world now, or them moving to Leviathan later).

If the plan is to play and journey together though, starting up a new character to play with them might be a viable (and free) option for now, and then you can figure out who moves, if anyone, when Leviathan opens back up because you might just prefer your new alts and what you managed to accomplish with them by then.