Welcome Nanny and thank you for posting. I agree with countries who pay for infertility treatments (with some limitations). I hope some day insurance companies or even some states will help couples out.
I know this may seem odd to ask, but has your husband ever been tested? I'm asking because it's easy to assume that because he has children, the problem is with you. However, secondary infertility (infertility after successfully having children) can strike at any time. Perhaps having a semen analysis done would be a good idea just to be sure?
If you've been trying for a year, it sounds like time to go and see the doctor and get checked out. Even if you and your partner have a previous child, secondary infertility can rear its head at any time and create problems where there previously had been none.
It could also be an issue on your husband/boyfriend/partner's side, too. You don't mention using Ovulation Predictor Kits (OPKs) but that might be helpful, too.
Are you tracking your ovulation? The Getting Pregnant Quiz notes that your most fertile days are "The 2 days before ovulation and the day of ovulation. A sperm has the best chance of reaching and fertilizing your egg in the 2 days before ovulation and on the day of ovulation. In comparison, the probability is just 8% three days before ovulation, and 0% the day after ovulation."
However, since you have been trying several years without results, it sounds like it's time to consult with your doctor. There's also a chance that your current boyfriend may have a fertility issue, too. Only by seeing a doctor and running tests can you find the answers.
I'm sorry you didn't get a positive result on the pregnancy test, but it sounds like your doctor has a plan to get you moving forward. Hopefully you won't need the specialist, but if you do, it's good to know that option is there for you.