One or questions for you. She is being faithful to you? Is she maybe seeing another guy or female?? Do you know for sure? If she is so "stressful" this is a sign that she may be seeing some one else. Another thought is that she comes from a family which her Mother was the ruler of the roost and was taught that sex was something that you did to have children or just to do the "deed" so you husband would not go else where.