I'm a complete newbie to the poly lifestyle, but I believe the more seasoned members of this community will agree with my advice--- seek marital counseling. Adding a relationship with someone else will not fix the relationship you are currently in.
I wish you luck and you have my thoughts and prayers.
Pinky, 41, f, bi. Married to Bear, 42, m, straight.
Not dating anyone right now.
I became insane with long intervals of horrible sanity.--EAP