I know this thread is a few days old but thought I would weigh in on this. Sorry about the length.

I've read books, articles and everything else imaginable to figure out why my W is in the same boat you are in. The only time she initiates sex is after about 2-3 glasses of Merlot. You could give that a try! However we are on 6 months of no ML at all, so that hasn't happened. I digress...In all seriousness though, I would highly suggest you have a discussion with your H directly about this. For the longest time I tried to ask my W why we could not have sex, and I got the same old story...I'm tired, the kids might get up, I have to get up early, etc, etc, etc..As I too had to deal with the rejection I handled it in a much worse way. I should have gone to the porn like your H. Anyway, since I couldn't get a straight answer from my W, I began to speculate and develop my own theories. The worst of which was that I convinced myself that she was attracted to someone else or better yet having an affair. This caused even bigger issues in our marriage. So the reason I say to have a serious sit down with your H is two-fold:
First, it will allow you to get these feelings off your chest and may also get your H's attention. Having an intelligent, mature conversation about your sex life is never easy. Work with your H to come to some type of solutions or goals. Perhaps a visit to your MD or OB might not be out of the question.
Second: It will definitely set your H's mind at ease knowing that you acknowledge the issue and that you want to work on it. Nothing pleases us guys more than to know that our Ws want us too, but are dealing with having a Libido problem.

You mentioned that you have 2 young kids. What I noticed is that after our kids were born my W's libido dropped dramatically. Mine on the other hand skyrocketed. I found a deeper love for my W than I could ever imagine after the birth of our kids. It was something I never could explain but I wanted her so bad it hurt and I couldn't think about anything else. So when your H tells you he wants you so much, I truly believe he means that. Women never will understand it until us men start pushing out kids.

Not to scare you but your problem is more common than you think. The good news is that there is help out there. You may have a hormone deficiency that is causing your libido to drop. In addition, most men have a hormone imbalance in that we are loaded with Testosterone. That hormone is the key to your sex drive. Do a google search for women with low libido. You will be surprised to see all that is out there.

As for your H getting upset and resorting to watching porn may be his way of dealing with the rejection. Us guys don't take well to being denied. If it bothers you that he watches that, don't be afraid to tell him. If you don't mind it then here is a little trick you can use to blow his mind. (No Pun Intended)
The next time you experience a rejection and he goes to the porn, try your hardest to stay awake in bed until he comes to bed. When he gets in bed to go to sleep, gently tap him on the shoulder and ask him directly, "so did you learn anything you want to try?" The look on his face will be absolutely priceless, I can guarantee it. Of course never feel obligated to do anything you are uncomfortable with. The only other thing I can offer is this. Guys are not the best at doing anything other than ML to show our W how much we love them and want them to be happy. On that note, don't be afraid to tell him exactly what YOU like/want!! Guys love that!! You may find that increasing the pleasure may increase your overall desire.