Simple answer - tell her no. I know it doesn't seem that simple, but if you guys are divorced and it doesn't have anything to with kids (don't know if there are any), it really is.

So I have a question for you. When you say yes when you want to say no and you do it anyway, how do you feel about yourself? How do you feel towards her? You must learn that your feelings and needs come first and foremost. Not that you can't see past them when it's important, but hey, she needs to learn that it's over. I learned the hard way that if you ignore your needs and feelings long enough, it will back fire on you. Hard.

I feel used she knows I will do anything she asked and she uses it to her advantage,

As others have intimated, and I have said before, with codependent adults, there are no victims, only volunteers.

If you feel used, its because you are permitting yourself to be used and manipulated, and not even intentionally by your wife.

Also, when we enable others to develop an unhealthy dependency upon us, not only do we stop ourselves from growing into interdependence, we stop the other person as well. As long as you are always there for her, why should either one of you move on and create a new and more fulfilling life?

Thanks now I just have to stop helping her all of the time

Exactly. And do NOT guilt yourself over saying no. You don't even have to justify your saying no either. When she asks why, you tell her that it was your decision. It's not about control or manipulation. It's simply about doing what is right for you for a change.

That being said, if it relates to your kids, be understanding for their sake. Like if they need clothes, need to visit you cause they miss you, whatever. Do nothing for her until she gets the idea that you will not be manipulated.

I will warn you though that there will be backlash when you start to say no. It's very empowering and it will feel good, but there will be backlash. I'm dealing with that backlash now (you don't want to take care of me when I'm sick). When the backlash starts, hold your ground.

What I did was start asking her to do things for me. you will either get to turn the tables or have a good reason for not doing things for her. As a side question ... do you help her hoping to get sex in return?

No I don't get any sex I wish lol