Any chance you could set her up with someone else too? That could be interesting
Especially as you're not the jealous type, you could encourage her to go for it... Maybe she wll start to get it. IMO a lot more people are poly than realise it. For me it activated once I realised it was an option, I started really noticing and caring for other people and now I can't seem to go back to only caring about one person in a relationship.