Hi Howsas,
I'm sorry you're going through this, I can relate in some ways. There's a reason you allowed yourself to get emotionally attached to om, something wasn't right in your marriage, you just hadn't pinpointed yet what it was.
Based on your description of your dh's recent abusive behavior, I'd bet a lot of $$$ that he was already emotionally/psychologically abusive. You may not have recognized it as such, but it would fit the standard pattern. You need to get you and your children out of that house before there's a further escalation of violence. That's priority #1. I am in that exact process right now, I'm not waiting for another escalation with my dh. I have an apt lined up for July 1 and my son and I are moving into it. The movers will be moving stuff out of the family home while dh is being served his divorce papers.
I have an om, but my husband and I have been separated living under the same roof for the past year and a half. He doesn't accept that it's over, despite having been told in words and by very obvious actions on my part. I met om after the separation but if dh found out, he'd totally view it as an "affair" despite his and my romantic/sexual relationship having been over for a very long time. I'd wind up in the ER or morg if he found out, he has an ungodly temper and gets off on physically intimidating people to get his way.
I'm not leaving my dh for my om, I emotionally left my dh in 1996 after he beat the crap out of our son because "I wasn't paying enough attention to dh". Nice, what a jerk. Om is everything my dh is not: emotionally in touch, highly intelligent, sensitive, sees the real world around him not the one he chooses to see, and he is genuinely kind and gentle (unlike dh who pretends to be kind in public but is a tyrant and bully at home). I have zero guilt about om, none, nada, zip!
Sorry this is so long, but your post struck a chord with me and I felt the need to respond. Contact your local women's shelter, they can help to advise you, even if you don't need to shelter with them. I got a huge amount of help from the group in my town, the women were extremely supportive, patient, and informative.
Best of luck and please seek some support.