Hello everyone!
Lately I've been doing community lots wedding parties with THIS mod.
The problem is that guests leave very quickly (almost as soon as they arrive at the church) and that's a bit sad. It makes all my efforts pointless.
Is it a compatibility issue? Is there a way to fix it? Maybe I should use a better mod (if there is one?)
Thank you in advance!

The mod that I have, that encourages Sims to stay longer in church, is BoilingOil's Need Freak available at LeeFish. It can take a bit of adjusting to get it right, and I probably should relax the settings at St Simeon's Parish Church for regular Sunday services. But I now rarely have Sims leaving immediately. There have been occasions when the Rev. Elspeth Anderson has preached for over three hours on a Sunday, and in those circumstances, she really shouldn't be surprised if some of the congregation decide to go home! She knows to keep the sermon short at weddings though. Don't get rid of the Community Lot Parties mod though -- Need Freak serves a completely different purpose.

Actually when my Sims have church weddings, they tend to have the reception and wedding breakfast at home after the church service. (When I think about it, Club Venezia on the other side of Veronaville would be a good place for wedding receptions. It has a large restaurant, a large dance floor, and a bar. Don't look for Club Venezia or St Simeon's Church n your Veronaville; they're both lots that I added!)

Thank you! I don't know this mod, can you tell me if it's incompatible with other mods? And how does it work in my case? I'm looking at the mod and it's made to control motives, right?

It's a very configurable mod, which can make it complicated, but it's also an object mod, which can only affect the lot that it's placed on. In my case I only have it installed on one lot -- St Simeon's Parish Church in Veronaville. I set it up in November 2020 for a big double church wedding (Andrew & Julian, and Gloria & Garry) and I've never changed it since. I think though it's probably time that I looked at the settings again. I set the minimums for Hunger, Energy etc. quite high as I didn't want anyone starving or passing out during the wedding. Some of my Sims are regular churchgoers, and everything has worked ever since. The only problem is that my Sims can't go for a restaurant meal after church because the Need Freak makes them never hungry. (I can easily get round that problem by using the Sim Manipulator to set their Hunger level to 50%.) I'm not aware of it clashing with any other mods, and I play a fairly heavily modded game. Because it is very flexible and configurable it takes a bit of understanding to set it up, but I've found that, once you've set it up, you can pretty well ignore it.

You can download it on Leefish here.

Ok, so, what I'm understading is that my sims leave the party because the motives get too low. But with this mod the motives get "paused".
So once you leave the lot the motives start decaying again on their own or do you need to "unpause" them?

Looking over the mod description, it should only affect the current lot, so no, you shouldn't need to unpause them.

Sims do periodically leave the community lot though (and new sims show up in their place), so another thing to try is to create a group and make your comm party a Just for Fun Outing. That way, if motives are good, all the sims you invite should stay until you end the outing.

Nopke has a bigger group mod here, if you need.

Another thing to try is Inge's Meeting Controller on Simlogical here. The downside with that one is that you'll have to set up the tokens for every single sim you want to invite and they'll be selectable, but the upside is that they will definitely stay until you End the Meeting.

So a few options here--I think starting with making sure motives are high is a good place to start. If you want sims to eat and dance and do wedding reception-type things, then I would just use Need Freak to make sure their motives don't get too low, making sure energy, hygenie, and hunger don't get into the red. Maybe comfort as well. I might max hygenie, but otherwise raise the other motives to about half only, so that they will want to eat and do something fun, etc. IIRC, if sims' motives drop but they can handle it on the lot, they will generally do so. It's when motives fall into that critical level, or it they can't take care of motives on the lot that they leave.

If you are finding that your sims' motives are fine and they are still leaving, it could be just that there are too many sims on the lot and the game is trying to manage lot population. Oh, another thing to try is putting this cheat in your userstartup:
intProp maxNumOfVisitingSims XX

Replace XX with the number you want; I usually do 30. This number is the number of visitors allowed on community lots (including the secret society lot!) and includes any npcs on the lot--servers, cooks, the host, baristas, djs, etc. So if you have a lot of NPCs on the lot, you may need to adjust this up.