I'm hoping this isn't old perspective. If so, just ignore or delete.
But here's my take:
Ron is no "love of my life" kind of guy. If you remember the 911 call, he had no trouble calling M a B*tch in no uncertain terms. He's had both drugs and violence in his past. Both are limited in education and values.
(IMO!) I'm thinking he was into some folks for either drug money earned, unpassed; or owed, unpaid -- and the minions came calling while he was away and M was there. In the heat of the moment and not fully realizing the consequences, he calls 911. Soon after, he may not have known exactly who, but he knew why.
If Misty gives it up, he goes away for a long, long time. His Mom would probably never forgive him (far more important than Misty's love and affection.)
Once it seemed likely that Haleigh was not coming home, the charade began in earnest. I shield you. You shield me. If we give the upper echelon up, she will never come home; if we give them up, we're also as good as dead ourselves.