Welcome to our forum.
I am not quite in the same situation, but I am in an MFM "V" -- in this case a married couple, plus the wife has a "non-legal husband" in addition to her legal husband. I am the "non-legal husband."
Most poly situations have their rough spots, especially in the beginning. I would suggest talking to your husband about ways to make your time with him more special -- some way to help him feel less "left out." See if you can get him to talk about what he needs.
Have a look around on our site; see what threads interest you. There is a lot to learn here. Post any thoughts or questions you have as you go along.
I'm glad you could join us.
Love means never having to say, "Put down that meat cleaver!"