What should I do about my husbands excuse for cheating?

I found out that my husband has been online talking to other women and on the phone chat lines and even ended up meeting one girl. He told her that he wasn't married and didn't even metion to her that he ha a son. I found her number and called her so he couldn't deny that one. He told me that the reason he cheated was because he didn't have enough athourity in the family because I keep him from discipling my children (his stepchildren). He trys to ground them for stupid stuff and takes out thier light bulbs when they leave a light on in thier room.. I think this is senseless do I told him I would handle my kids and he says that is the reason for cheating.....