It's very common for depression, anxiety, PTSD and more to affect a couple's sex life.
According to YourTango Expert Dr. Stephanie Buehler, "many people are completely unaware that they have a mental illness, let alone that the mental illness is affecting their sexuality." Here, two experts discuss the ways in which mental illness affects a central aspect of couples' lives—their sexual enjoyment of each other. It is a highly unexplored topic with little research, and we think it's incredibly important to shed light on it so that couples can begin to work toward happiness in this area. After all, according to oursurvey of mental health professionals15-30 percent of married couples struggle with mental illness (that's as many as 3 in 10!) 

When it comes to having an effect on sexual enjoyment, mild depression and anxiety are very common. Depression can cause someone to feel shut down and withdrawn. Depressed people will often say that they no longer enjoy something they used to, sex being one of those things. 
Read the full article at Your Tango