Adopted child PARTNER?

Hey all, I have what is probably the stupidest error ever in my game. I have a sim who is engaged to another sim, and they live together. I had them adopt a toddler girl. I have no idea how it happened but somehow the adult male sim and the toddler girl are listed as each other's "partner", despite still being listed as father and daughter in the relationship panel. The adult are still called each others' fiances. I thought maybe marrying the adults to each other would fix it but I can't get the have wedding command to show up. The only thing I can think of is killing off or deleting the adopted toddler but if there's a way to fix it without the nuclear option I'd prefer it.

To be sure, I've modded the shit out of the game, mostly with NRaas' stuff. I haven't tried playing without the mods. Any advice would be greatly appreciated since I've had this household for a while and I don't want to delete or have to start anew. Thanks!

First thing I'd recommend would definitely be playing without the mods, and also making sure that all of them are updated.

Thanks for the responses, sorry for not replying sooner, I rarely have time to play much. Lady ElDi, do you know where in Master Controller or what settings I can use to try to repair these relationships? I know there's an option somewhere, maybe Master Controller-->Intermediate-->Family, or something like that (I don't have the game running atm) where you can set a familial relationship between two Sims, but that doesn't seem to be what I need.

I noticed somehow that the household thumbnail managed to reflect this screw up too, so the Sim has his arm around the toddler's shoulders and the toddler is standing but in that revolting stretched-out form that is used for toddler errors, like when forcing a death or something, and the female adult Sim is just standing shyly in the background. If I can I'll take a pic of it and post it just for laughs. It might indicate that despite the retention of the fiance status for the two adults, there might be some partner setting to change up--? Maybe someone with way more knowledge and experience of the game can verify, I've really only had it for a couple of months. Thanks for any help.