Is infertility possible?

I am in a gay relationship and my wife and I have been trying to conceive. I tried several months with at home AI with no success so we switched to NI for several months and still nothing. I was ovulating according to tests and my temps but nothing. I had the Paragard IUD for not even a full year and I am almost 28 years old. Is there possibly a problem? Would I still ovulate of there was an issue? We had kind of given up on me and now she is trying but I'm just not ready to give up the thought of me ever carrying. I'm having a really hard time dealing with these thoughts. Any ideas or suggestions??