Last hope with IUI and follistim.... Please advise

Ok so I have not been on this board for a year because it has been just too emotional for me. To recap my partner and I have been together for seven years. We have a 12 year old from a previous relationship of mine. We have been tttcfor three years now. We started with three ici cycles at home all BFN. We then did two IUI cycles at home , again BFN's. We went to an RE did three unmedicated IUI cycles all BFN. Switched to a new RE and he put me on 100 mg Clomid and Ovidrel trigger resulted in BFN. Did another same protocol the following month, BFN again! I then had a Hysteroscopy witch revealed three unterine polyps which he removed. The very next cycle we did the same Clomid + Ovidrel + IUI and still BFFN!! My patner and I have been on a rocky road and we fight every time we get another BFN. This is our last cycle and the RE has moved us onto injectables. He has recommended 75 iu Follistim for ten days + Ovidrel trigger + IUI. It is very expensive and K, my wife, does not want to do any more after this. Can anyone tell me what my chances are of this being it? I am so scared to try and have another BFN. I hate to spend all this money and it still does not work. Has anyone had anything similar and gotten BFP on their first injectibles cycle? Thank you so much and baby dust and GL to everyone who is also on their own baby journey! I know how hard it is!!!!