https://www.gamespot.com/articles/stardew-valley-still-coming-to-vita-multiplayer-be/1100-6455514/

Fans will have to wait a little longer to try out Stardew Valley's multiplayer update. Developer ConcernedApe initially planned to release a multiplayer beta by the end of this year, but that has now been pushed back into the first quarter of 2018.

In an post on the game's website, the developer explained that the reason for the delay was in order to "make room for polish and QA." Despite pushing the beta back, ConcernedApe says the multiplayer update is "coming along nicely." Among the features the developer is working on implementing is the ability to marry other players.