What to do in a failing marriage?

Been together almost 6 yrs , and hes totally alienating, non-affectionate, never wants to do anything together, sometimes down right hateful. This man is the one and only love of my life, the only man i have ever been inlove with. We have a 5 yr old daughter, and she will be effected deeply if we divorce. I've tried to be romantic, caressing, caring, attentive, and I get nothing in return. Not sure what to do, or how to fix this, or if its fixable. I moved 2000 miles from my home and family for this man. I've asked him whats wrong, and he just keeps saying the same thing, "nothing". I thought maybe he was in a funk, but I dont think funks last a couple months. Please, how do I fix this?