As the author pointed out, jealousy is about insecurity, not love - that's just a culturally constructed idea straight out of patriarchy, where you are supposed to own each other and the man in particularly, is seeking to keep the woman away from other potential partners so that he can verify that any children are his.

Imagining that we can only love one person at a time is a part of this same construct and scarcity mindset. Love is the most abundant thing in the universe and although that doesn't mean that transitioning away from monogamy is easy or simple, it does mean that if you've done a lot of talking beforehand, which it sounds like you are doing, to open up from a place of agreement and cohesiveness in your relationship, then the love part shouldn't be an issue.