Sim being moved in with another Sim while I'm playing a different family

.....And now a pregnancy has started between them. This is ruining my game play. 

@gertie47 

The easiest way to keep the MCCC story progression from affecting sims you don't want it to, is to keep them marked as played with the bright green plumb bob.  And if you have Neighborhood Stories enabled for played sims, disable it in Manage Households.

Hope this helps.

@gertie47 

MCCC will still affect households in the played section if they don't have the bright green plumb bob.  If they have the light green plumb bob, MCCC thinks they're fair game.  The move into together is MCCC but the pregnancy could be either MCCC or Neighborhood stories.  

There is another way it could have happened though.  Those phone calls that you get asking (I found a ring in so and so's bag) should I get engaged/married and should we have a baby?  Both things will cause what you had happen.  But you have to choose on those, and it would have to happen twice.  I know I have inadvertently answered several of those the wrong way.  Do you remember getting any of those calls?

Hope this helps.

@gertie47 

That sounds like a plan that will work.  But, if you have to do that for every sim, then it's going to be a bunch of extra work if you have a lot of sims.

You shouldn't have to do it though.  I use MCCC and it took me a bit of experimentation when I set up a new long term save, but I was able to stop things like that from happening.  At first, I was having move ins, marriages and babies.  Now I don't have those things going on.  So, it can be done, just takes a bit of time to get it right.  You might want to experiment with the main settings a bit to see if you can get to that point as well.  I used a throw away save to do it so I didn't impact my main played save.  But it's your game so you do what you have to do to get the game playing the way you want it to.  

Hope this helps.

I finally got back into the save and tried the suggestions to flag things for this sim, but it didn't register it seems, as when I went back to his original family, I got the same pop up to say he'd moved in with another sim as they wanted to take their romance to the next level, or what not. 

I'm tempted to move him back home, to be honest, and move him out last after the other sims do what the need to do, and then marry him to someone while he lives in his new house. So he stays put. But it doesn't fit his storyline. 

I've never had this happen before. That is the crazy thing. I'm also wondering if there is some new underlying coding in the game since the last update, considering the next expansion pack is about being "neighbourly", and maybe it will entail an expansion of what neighbourhood stories can do - and it is that which is clashing with MCC. 

I don't know if anyone else has the experience of the pop-up I was getting; I have never seen it before in the game. 

@gertie47 

You know, just thinking about it, I have never seen any popup like that in MCCC or the game.  Are you using any other mods that affect relationships and moves, marriage, etc. autonomously?  

Are you sure you have Neighborhood Stories turned off for that household.  NS doesn't marry sims afaik, but it certainly will move sims and generate babies and adoptions if you have it on.  I'm not sure if it will move sims in together now as I have it shut off.   I haven't used it in a while, but I did try it for a while but didn't like the chaos it was causing in my save so I shut it down for the most part.  Now I only have it on for the NPCs in the Other tab and only the deaths even there just so I keep getting the NPCs changing over.  

Hope this helps.

So I think I may have been given the solution and I have now set the relationship move-in percentage to 0. It is the next sim day, and I've had no pop-up to say my sim has moved out with one of his boyfriends or girlfriends 😀 .

As long as the sims in the surrounding worlds continue to get married and live their lives, I think I may have found the solution.