Hey, welcome to SK.
I had secondary infertility as well.
Have you had any testing done on yourself yet? My problem was blocked tubes, and of course I had no idea, so it was a long 3 years of trying before I knew this. If you havent already I would suggest that you have a HSG(hysterosalpingogram) done on yourself too. It could save alot of wondering. I am not sure if you have had any testing or not, but it is a good place to start.
Good Luck to you
I hope you become pregnant really soon