Lying to your wife, hiding your relationship, and maintaining secrecy is NOT poly. It's cheating. You can call it whatever you want. However, if you are not being honest with your wife, you are cheating.
Do with that what you want. However, continuing down the path you are going can easily destroy your marriage.
Personally, I've lived through both consensual openness and cheating in my marriage. The consensual openness and now the poly has NEVER been an issue in my marriage. The cheating nearly destroyed us. It destroys 2/3 of marriages where it occurs, actually. Anyone who has survived cheating can tell you it's not the SEX that is the deep, devestating blow to the relationship. It's lying that destroys a relationship, not the sex.