Hi Artsychick,
I agree with bigkahuna, you need to talk with a pro-marriage counselor. Your husband can change, but he needs to know first how serious you are about your emotional needs being met. Tell him through both encouragement when he does bathe that you enjoy being around him that day, and want every day to be like that. Don't tell him days later, tell him that day, with positive comments. Remind him to change and brush his teeth each day. Take his clothes and put them in the washer so he has no choice but to put on clean ones. Do those things if you think it's OK to do them. I'm not in your situation, you know best.
Whatever you do, do not have the affair. Look at the A as the most hurtful thing your H will ever experience, pain you can't imagine. I know, my W had an A and if I had known it was coming, I would have done anything to have stopped it. Tell him you have fears about having an A. Warn him so he can change. If you have to, separate to get the message across, but do NOT have any A. Please don't do it. Imagine I'm your H telling you now, months later, telling you for him that it hurts him, hurts your marriage, hurts your kids, and will eventually hurt you with feelings of guilt and loss of feelings of love, caring and integrity towards your H.
Help your H be more of what you want. Tell him how A's develope, show him Dr. Harley's books about fulfilling emotional needs for a strong marriage. You will not regret this route, but will regret an A, and your husband will be devasted over it. Please don't do it.
God bless,
CS