Topic: Advice IUI v IVF

I am looking for a little advice.  We have just completed try number 5 and it was a BFN, again.   We have been discussing moving to IVF but I just checked inventory and our donor only has ICI and IUI left.  We really like this donor and don't want to give him up.  Does anyone have any suggestions or experience with not conceiving this many times in a row and then it working?