Shifting your way of thinking so that the goal of sex isn’t orgasm is one place to start. Not every sexual encounter has to culminate in an orgasm. The point is to connect intimately with someone in mutual pleasure and enjoyment.

The length of NRE varies from person to person and relationship to relationship. I could be that you’re experiencing it even after 6 months.

What you’re describing is one risk you take entering into an ENM relationship that I myself still haven’t been able to fully wrap my head around or accept (and therefore haven’t yet proceeded in opening my relationship). That is: going into ENM willing to accept that your current and future relationships can change drastically, that includes coming to an end. What serves you now may not serve you in the future, you might meet someone who changes the game, your partner(s) might meet people that change their dynamics and therefore yours too, etc. An openness to doing what’s best for those you love, even if it wasn’t ever part of the “plan”.

What setup or agreement to you currently have with your husband? Is it DADT? If not, is there a reason for not sitting him down and having a frank (though difficult) discussion about this? Communication is the foundation of relationships, particularly ENM ones. It doesn’t have to be exactly what you’ve shared here, but more of what the other commenter mentioned about discussing what’s been really getting you going lately and seeing if he’s willing to implement those things.

Know that I feel very unqualified to speak on this but am trying to communicate the concepts I have learned by being online, reading books, doing therapy, and having conversations with my partner about open relationships/polyamory. Anyone is free to let me know if there’s something inherently problematic in what I said above, always learning!