I don't know how else to word this, sufficed to say that it's kind of gross that you did that and now you're smug about it.
If you want to be with your W, she has to choose you. She has to want to be with you, willing and ready and able to work on your M.
She cannot choose that when you're "making her" think the situation is different than it is. It's dishonest.
In my opinion, it would have been a better moral move for you to say, "I've seen this; what's going on?", rather than delete it and be creepily delighted that you got rid of it and she'll never know.
You need to be a man worth being with, not someone that's tricked her into choosing you.
ME: 38 BF: 40 T: 10y, no kids, no M (by choice) BD: 7/14/14, BF admits to PA, wants out, lies about new R. 10/1/14: I move out, BF lies about move in with OW 12/4/14: OW confronted, reveals all the lies