How to break up with someone?

[summer_wine]

So i started playing the game earlier this week. it's so addictive

anyway my legacy sim managed to be in love with two people at the same time.  i had her propose to one and the other one to move in. now how do i break up with the one she's engaged to? i'd really like her to get married to the one she's living with because they have kids and one of her fears is to be of old age and not get married.

how do i break them up so she can get married to the other one?

btw, i'm not using any cheats or hacks. the only one am using is to automatically pay the bills.  thanks!

[MaryH]

You have to make the couple you want to fight-by letting their relationship self-destruct in any way possible; when it gets so bad that all they can do is "fight" then the option to "break up" shows up.
Irritate, and annoy seem to start it off.