Infidelity Support Group
Any relationship in which one partner engages willfully in sexual relations with another outside of the partnership is considered to have experienced infidelity. This breach of trust is often traumatizing for the faithful partner as well as the relationship, and support is often needed to heal emotionally and to decide whether or not the relationship should continue after...
Ever get to the bottom of him being absent? Was he away at work? Emotionally absent?
It doesn't appear he has very good coping skills to begin with as stress causes him to withdrawn and turn to addiction.
As such, it is highly likely that his coping regarding your affair will probably be self-destructive in nature. Revenge affairs are such things as they provide temporary relief from pain but come with more negatives.
You are both going to need significant personal counseling if this has a chance of working out. If he can't manage general life stressors in healthy fashion, even if you do absolutely everything correctly post affair he may simple be unable to get past this.
straying = adultery= cheating=infidelity = wallowing in ones own filth with another sneaky slime-ball ...just saying