This is a not uncommon problem in a woman of your age. There is no direct link between endometriosis and PCOS and low desire - this could cause you pain with penetration which could get you to loose desire for sex. Also no orgasm could make you less motivated to have sex. Low desire is caused by a multitude of factors which include fatigue due to young kids, resentment towards your husband that he doesn't help enough around house; discomfort in your own body or lack of your own sexual interest in yourself. If you do not feel sexy then its hard to want sex with someone else. And also having orgasms alone facilitate partner orgasms so masturbation is an important part of your own sexuality. . perhaps work your way through my book PILLOWBOOK as its a great self guidance process for women to learn and love their won sexualty. http://www.dreve.co.za/shop/books/pillowbook-by-dr-eve.html