How to Let Go?

Qianya
I've been a lurker until now but feel compelled to share my story. My partner and I have been trying to conceive through IUI since March 2014. I've had two myomectomies, a laporoscopy to remove scar tissue, a myosure and an HSG that revealed one blocked tube. 
Stupidly, I smoked during the first year of trying. Finally mustered the strength to quit and just did a 6th IUI with no luck. My RE wants me to have another HSG. And then we are trying a lucky number seven IUI before considering moving on to IVF. We really can't afford it. It will hurt us financially but I just can't let go of this need to be a mommy. 
I feel like I should just let go but I don't know how. 😔  Oh. I just turned 40 in May.