He will definitely need to seek help. My husband and I have been ttc for the past year. We never had any sex problems before but since we started ttc I noticed that at times my husband suffered from erectile dysfunction. At first I thought that he didn't want kids and that he was too scared to tell me. After about 9 months of ttc I realized that there might be a problem. My husband turned out to be azoospermic, his fsh and lh were really high and his testosterone was normal but in the low range. I realized that the reason for his erectile dysfunction was due to the fact that his testosterone level was going down. So there could either be medical problems or psychological problems which may be preventing your husband from performing sexually. If he is too ashamed to seek professional advice, then perhaps you could try to discuss this problem yourself with your doctor and see what needs to be done and then discuss it with him at home. Of course ideally he should go with you but I can imagine how stubborn men can be sometimes.
Does your husband have any health problems or on any medications that's preventing him from performing?