Things I have learned about being poly are: your marriage needs to be solid. You need to have a good understanding of yourself as well, and a strong ego.
Since you feel so very insecure and have abandonment issues, poly is not going to work for you if you don't feel secure in your wife's love and presence remaining constant.
Since you 2 stopped having sex only 2 years into your relationship, I'd hazard a guess your marriage isn't all that solid... what's getting in the way of your having a frequent, healthy, experimental sex life?
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
"Master," (mono, 34), miss pixi's Dom for 2 years