How do I confront my husband who may have a porn addiction?

I realize this is a very tough topic but I need some insight. Please no jokes or awful comments - my heart has been bruised enough.

We have had a lot of marriage difficulites in the past and recently agreed that we have a trial separation before we end up hating one another. So in the next few weeks I will be moving out. He thinks I am leaving because of a few issues we can not agree on and has no idea of the real reason I am leaving. I am unable to sleep as I worry he will masturbate and that is all I invision in my head. I recently went to my doctor and am now on sleeping pills and sleep in the spare room.

I know of his secret life looking at porn and masturbating. He's not very discreet covering this up although he only deletes internet history on the days he is looking at smut.

I know he will deny this and be very angry at what I am thinking or what I know but I do believe this is serious. He no longer feels passion towards me, doesn't have any desires to make love to me either.

I read online about this and it states:

In the case of internet use, only a short exposure is needed to turn a used into an addict. The internet offers the three A’s: accessibility, anonymity and affordability. It also offers extremes of behaviors that the hardware of our brain may not be able to handle. Like pornography it also has the power to change our ‘love maps’ or templates that represent what attracts us sexually. It is called the ‘crack cocaine’ of sex addition.

IF anyone out there is going through something similar, please, I need some support.