Promise Rings

I have been a long-time simmer but while I have kept buying the packs I haven't had a chance to play for a long while, I apologize if this is a rehash of an old topic.

I created a household with a teen sim and he exchanged promise rings with a female teen sim. The during high school he developed a crush on a new sim and their relationship bars are both now maxed out. While I have been able to make my sim and the new sim boyfriend/girlfriend I cannot get him to exchange promise rings with the new girlfriend as it says he is already promised. His relationship with his 'promised' sim is now angry after he broke up with her. Sorry, I hope this all makes sense. Is there a way to take back the promise ring or cancel romantic relationships somehow?

I don't use mods but would be happy to use cheats if there is no way around this. Otherwise will probably start all over again.

Thanks for any assistance!