I've always had dramas getting UTD. Took 2 years with my first pretty much straight away with my second and 18 months with my third.
With my third I did 6 months naturally and then 8 cycles (8 months) of clomid with 1 MC and then straight into IVF. Trying for my 3rd was when I was diagnosed with PCOS.
. I hope your BT can shed some light on whats going on.