Infertility

So I know I may be to young to worry about this (I'm 20) but I've been having unprotected sex with the same guy for 4 years (we've been together 5 years) and I've never gotten pregnant. We've recently noticed his libito has decreased dramatically over the last year (possible ED) and I had ovarian cysts in 2012. I heard that can cause infertility/endometriosis. I've looked up signs/symptoms and fit a few of them. Also I'm worried that my boyfriend may also be sterile (simply because of all the unprotected sex and lack of sex drive) i just want to know what you guys think? Should I see a doctor? I may be young but I'd like to have kids in the future...