The story y'all have heard before

She has the same financial motive to remain in the marriage as you do. No judge would award her the same level of support she currently gets (assuming you're working). She can perform basic math functions. I expect the trouble you have is that she believes her bread is certain regardless of her performance. She treats you like crap because she can without suffering any adverse consequences. Without telling her "why" and without complaining about anything, I would make myself as scarce as possible. I'd find something interesting to do somewhere there was an abundance of available, attractive, realistically possible, mate replacements. I'd continue supporting the wife, but only to a level slightly higher than that which would shock a judge. If she has a brain, she will put two and two together and arrive at the conclusion that if she wants to keep you (and your bread) she'll get back in the game or lose you to the competition. I probably wouldn't actually have an affair but my wife would get the message that attractive options were available to me and she didn't have a divine right to me as her husband.

OP,
I'm trying to determine if this is just a libido issue or if there are more problems in the marriage. You say she is your best friend and the love of your life. Are you her best friend and the love of her life? You say that you were waiting and hoping for her to love and want you. While those two things should go together, in her mind, she may love you but simply have no desire for sex. Do you feel that she is unhappy in the marriage? Has she complained or spoken to you about anything else that might be bothering her about the marriage?
What she said would be a horrible blow to take and I'm sure that you feel crushed. But don't give up yet. What kind of communication have you had with your wife about the lack of sex? Or have you just silently accepted it over the course of your marriage?

Before you declare divorce to be unaffordable you need real facts. The web can give you a good idea of how child support and alimony tends to work in your location. A lawyer will usually give you a free 10 or 15 minute consult where you can ask some basic questions and get expert advice on what you are facing if you do divorce.

Your happiness and self respect are worth more than a little money.

Yes I think you should try to improve your marriage or at least to understand how things got like this. How did you select this person? Why have you let things get like this? Are there changes you can make for your own betterment now? Is there a way to enlist your wife in a good faith effort to resolve your marriage problems?

So I wouldn't jump right to D based on your first post. But I think you need real info before you exclude any options.