I am in a similar situation to you (fairly new relationship, married for 10 years), and my advice is to not be too hard on yourselves. Expect there to be differences between your relationship with your partner and your relationship with your husband - your new relationship doesn't have the encumbrances of day-to-day domestic issues and is exciting and unfamiliar.
Enjoy and appreciate what you have with your husband, and make time to reconnect, talk, make plans for the future etc. Make sure that your new relationship is working out for all three of you by checking in and making sure your husband is alright with the way things are - a poly relationship is exactly the same as a mono relationship in the sense that compromise and being aware of the other person's feelings need to be top of the agenda.
As far as my own situation goes, my husband and I have reached a new level of openness and depth in our relationship. He now has his own girlfriend, although their relationship is considerably less involved than mine with my boyfriend, and her existence makes me a lot happier (and obviously him as well
). I really appreciate the qualities he has and have made that clear to him, and he knows how much I appreciate both my relationship with him and his acceptance of my relationship with my boyfriend.
Good luck with everything!