is famous for having planned celebrities' weddings over the years -- but now, he's gonna have to plan his divorce ... 'cause his husband's throwing in the towel.

According to new legal docs, obtained by TMZ, Joey Toth just signaled in court that he wants a dissolution of his marriage -- citing irreconcilable differences ... and also listing the date of their separation as the same day he filed for divorce -- and that would be today.

There are a few things Joey wants right off the bat in his petition -- for starters, he wants David to be ordered to pay spousal support to him ... and for a judge to make it so David himself can't receive any alimony from Joey.

As far as their kids -- the couple shares two young children, aged 4 and 10 -- Joey has some thoughts on that too ... but on that front, he's more open to sharing. Joey is asking for joint legal and physical custody.

One last thing ... he's asking for is David being ordered to pay his attorney fees. The other interesting thing worth noting is the fact Joey actually filed for divorce from David in 2020 -- this after they got hitched in 2017 -- but he withdrew that at the time, per court records.

Sounds like things have gotten rocky again, 'cause he's pulling the plug officially.

Tough break for a guy whose whole life has been organizing people's happiest days. Better luck next time, we suppose ...