Sims won't get engaged?

[Kuro-rin]

So I'm currently playing a full house of sims, and for some reason, my sim can't get engaged to his girlfriend! They've been boyfriend and girlfriend since they were teens, so there's no problem with their relationship bar. This is the first time something like this has happened to me and I have no idea what to do. I really don't want them to break up because he just got the "faithful" reputation. Can anyone help me with this?

(I'm sorry if this is the wrong place to post this)

[Trip]

You can't propose to anyone outside of the household if your household is full.

[Kuro-rin]

You can't propose to anyone outside of the household if your household is full.

Really? Even if they're just going to be fiancé and fiancée? I didn't know that (haven't played many large familes)
Looks like elderly dad won't live to see his son marry then
Thanks for the reply!

[Shirin]

Really, because once you're engaged, you will get the option to have your wedding, which then allows the possibility of moving the spouse in. Since you can't do that with a full house, you can't marry.

[Kuro-rin]

Really, because once you're engaged, you will get the option to have your wedding, which then allows the possibility of moving the spouse in. Since you can't do that with a full house, you can't marry.

I see. Thanks for the info!