Since you have a full-time job and are earning 'peace of mind' money as you put it, you don't HAVE to be working non stop to make ends meet, so you can afford some time off - I recommend you take at least 1 entire weekend a month and either go camping / holidaying away from home, or if that's not possible just make a commitment not to spend it online.
Going away for the weekend works for me, it forces me to be away from the temptations of the interwebs, and the gf (wife in your case) appreciates that she gets alone time with you. And she doesn't give you so much flack then when you do spend long hours online the other nights / weekends.
And Marusia is 100% right, when you do then get into it again, you actually work harder and are more productive than before.
I'm trying to explain this is why i need a 3 day weekend every week, but my boss isn't buying it...