I feel really sorry for you! I know what you're going through.
I can't help but wonder if the age difference is a contribution to the problems. You are a basically a generation away in age. I was in a very unhappy situation with 9 years age difference for 10 years.
This is not saying it can't work though!! Not at all!! But what really matters here is that your need are not being met and it seems he don't want to do anything to correct it. If he won't even talk to you without getting defensive, he must know he is doing something wrong.
I don't mean to sound cliche but you could try the old never say "you" when talking about problems. For example don't say "YOU never take me out or spend time with just me anymore!" (he will take offense to this by reacting back with a defense..."well, YOU don't seem to have fun when I do, so why bother")
Try saying something like this instead, "Honey I want you to know that I really love you and I want us to be very happy together and "I" know spending a little more time together would really make "ME" happy" (You see...not nearly as likely to trigger a defensive response)
It's really hard to do this sometimes so you might want to take a second to think your replies out before you actually answer...practice it in your mind for a couple seconds first. I am not saying this will always work either but what do you have to lose? You got to make him understand what he is doing to you...maybe he is so wrapped up in his work and stuff he really don't see it. Or maybe he knows and it isn't a priority, if that's the case..get out and find someone who wants to be your partner always, not just when he can fit it into his schedule.
Good luck and keep us posted!
Never be afraid to try something new.
Remember that a lone amateur built the Ark.
A large group of professionals built the Titanic.