It's so tough when it drags on!! I am in very similar boat - have been TTC for about 20 months and have short luteal phase. Great that your DF has got you UTD before though!

I have had everything tested and there is nothing else 'wrong' as such, so my FS has prescribed me Pregnyl 1500...
which is a a booster which will hopefully assist with implantation. I have to have injections 4DPO and 7DPO. I can let you know how I go with Pregnyl if you like... I have a feeling it will make all the difference!

Hope your test results are all good! best of luck.