EU Family Member Visa for my Unmarried Partner?

I am Czech, my partner is Ghanian. We live and work in China and want to travel to Europe together in the summer to visit my family. The application has an "other" option which I am told includes unmarried partners IF you can prove your cohabitation and durability of your relationship. So that's what we're planning to do.

But reading a few posts here has made me really nervous as you guys seem to think it will be impossible? Any tips or success stories?

Full disclosure, my BF tried to apply for a standard tourist visa 3 years ago - through an agent - and was rejected (10. information on the purpose of travel unreliable?) This was before me met which is why now I want to use my EU status to our full advantage.

Any help would be much appreciated!