Bobbib
firstly, I don't know you age and if you're still young, you have the time to just keep on trying with the temparture method to see when your ovulating. If your cycle is 28 days...Ovulation is about the 14th day, if you're irregular...It's better buying a testkit that indicates exactly when your ovulating.
If you're nearly or over 30, go see your gynecologist because it can takes between 3 to 4 years to get through all the tests to find if or where the problem lies. I've been through it all and in the end they found that my tubes were blocked (histerography and after coelioscopy) so even though I ovulate correctly, hubby is fine, sperm is active after sex (huhner test) and all my hormone levels and secretions, ect. Are fine, I still couldn't fall pregnant naturally....After all that, there's a waiting list for assisted pregnancies and this can takes years to be succesful. I was lucky, the first one has worked so far but a colleagues of mine took 3 years....
Best of luck to you and your hubby...Enjoy trying;-)