I have to commend you for at least exploring polyamory as an option and looking for what might work. I hope you and she can talk it out and be open to creative solutions. Life is too short to give up on your sex life! Too many people are out there suffering silently. Kudos to you! She's a lucky woman.
Also -- maybe SHE would be the one overcome with NRE with a new girl! Hmmm.