What a weekend girl! Sounds like you handled yourself excellently. Good job. I am sorry for all the pain that this betrayal has brought to you. You deserve none of it, whether or not your marriage was poor in the past. I want you to remember that, Deb. People make mistakes, we forget to listen, take eachother for granted, etc BUT that does not give a partner the right to have an affair and certainly not to keep rekindling it and lying about it.
I too think that giving him two weeks (frankly, even allowing him to come up with the time-frame) is too easy on him. But, hey, it's a done deal now. I do not think that I would go back and change it now. I think that by saying that he will break in off with her by June the 1st, by telling you that he needs to say goodbye to her daughter and that he needs to do this "well", is a case of him pushing the envelope. He is testing you to see just how much you will let him slide. (Like a teen does to his mom.)
It's time for you to decide what is acceptable to YOU. What do you deserve Deb? And then you need to communicate that to your h in no uncertain terms and remain unwaivering. Some people have given you a few ideas like a new cell phone, ow crap out of your house, no more paperwork on Saturdays (real or not), new job, etc. Make a list if you need to about what would make you feel more secure in your relationship. And what about the ending of their r? How do you see that happening? Would a face to face meeting, where all three of you are together in the same room when he tells her, make you feel better?
I just shook my head when I read about your h getting angry with the people at work for snooping. Does he ever accept responsiblity for his actions? He's been really great at blaming you and when he sees that that won't work, he blames people at work! Beyond ridiculous.
I think that these next two weeks need to be "Deb" weeks. Put total focus on Deb, her son, and achieving those goals that you listed. (Good goals, btw.)
I think that I would be selfish with my time and affection until I had some of my needs met.