Thank you both so much for your comments and advice. After being in turmoil all week about how I'm going to handle the intimacy situation with my wife, I think I've finally made some decisions. I'll post them in detail when I have more time, but in short I've decided that even if things don't get any better than they are right now (intimacy-wise), I want to spend the rest of my life with my wife. I love her and need her. I want to be able to tell her that I love her and call her just to say hello, even if doing so doesn't help my "cause". I want to be able to spend time with her alone - go to movies, go on trips, etc. - even if there's no chance we'll have sex. Granted, being able to do those things while at the same time having a fulfilling sexual relationship would have me smiling from ear to ear. But I'm not prepared to give up an otherwise wonderful marriage over a lack of sex.
I have a question for both of you based on something that Lis said. Let say I stop initiating anything physical and explain to my wife why I'm doing so. If the opportunity to take a trip somewhere together (long weekend, etc.) should come up, would it be okay to say "let's go on this trip with the understanding that we will not do anything romantic - no cuddling, kissing, sex, etc. - let's just have fun with each other with no romantic expectations"? I think that would help me a lot, because if I went on a trip knowing that nothing would happen, I wouldn't get upset halfway through when it didn't. Let me know what you think. I'll post more later.