Advice on how to bring this up please?

Tried this question before but apparently worded it horribly, so just trying again. Me and my fiancee have been doing some ual exploring, and I am extremely bi-curious, not looking for a relationship, just physically curious. From the fact of her being turned on to an extent by gay I wonder if she may enjoy seeing me with a man, and I am very open to trying it. She comes from a very old school, phobic, family, and they are also shall we just say repressed. I'm looking for a way to find out if this may interest her w/o sounding like I'm looking to cheat, or freaking her out etc. Not looking for moral objection, etc, just creative/innovative suggestions for opening the subject with her. Thanks