Wanting to give up

I have always had a plan that I wanted to start trying to have a family when I was 21 and I'm now 24 years old and my fiancé has made it official that he doesn't want to try anymore cause we aren't ready....he just wants to work all  the time and says he is the man and it's his responsibility to take care of me.....he was ready and everything changed but he still wants to marry me....I just don't understand or know why he changed his mind and now I'm to the point I don't even know if I should even think kids will be in our future and it didn't help we were trying for almost 3 years.....and nothing has worked.....*sighs* I'm just giving up.