After thinking about it, I'm bogging you down with WAY too many personal details.
Let me see if I can simplify this:
You, your husband, and son - a legitimate family in the eyes of God and state -- are like Barbie and Ken with a baby. What's there not to like?
But Ken has a dirty little secret. He's hooked on cocaine (aka his mistress), and he refuses to give it up. He is NOT himself. Anything he says under the influence of his drug should NOT be construed as truth or his final word.
To get him over this drug, you have four choices. You can:
1. Kick him out the door because of the addiction.
2. Learn to deal with the addiction, hope he overcomes it and returns to you in time.
3. Stage an intervention and force him into rehab (exposure and no contact).
4. Give him a "drug" alternative that's better than cocaine => you! (Larry's method)
Let's be clear about one thing: the addicted WH is not YOUR husband. He may look like him, talk like him, and even smell like him, but he is NOT the man you married. He's an addicted shell of the guy you said "I do" to. If you can drill that into your brain, everything else becomes MUCH easier...