Denying sex to your spouse

Is there anyone out there who is married and hardly ever wants sex? I am a christian and have read that it's a sin to "deprive your husband." Does that mean that I should do it if I genuinely do not want to? I am at a point in my life where I feel nothing but stress 24/7. I work full-time, go to school full-time, have a weekend job, and do everything around the house. At the end of the day I don't feel relaxed enough to have sex. Most of the time I just need a few minutes of alone time and then want to sleep. 

What should I do?