Unexplained Infertility

So I have gone to the doctor several times. Had all the blood tests. My husband had the sperm test. and Monday I had an HSG which showed everything as normal. Does anyone else have this problem and have any words of wisdom for unexplained infertility. I am 25 years old, supposedly healthy and I have been trying for 15 months. very frustrating and I am very discouraged. my doctor wants me to see a specialist and start treatment but my husband thinks we should wait it out since there is actually nothing wrong. Help!