TTC for 1 year: HELP

Kay • 1 healthy 4 year old. 4 early m/c in the last year. TTC for baby #2!
My fiancé and I have been trying to get pregnant for 1 year. I have a 4 year boy from a previous relationship born via c section. My fiancé has a 6 year old daughter with a previous relationship. 
We unexpectedly got pregnant September 2015. Ended in an early miscarriage. 
December of 2015 we decided we wanted to actively ttc. Since we have had three more early m/c
My ovaries look fine. My lining and uterus are normal. Even though I have a tilted uterus. 
Failed SHG. The doctor said my cervix was closed and tilted and couldn't get the line past my cervix. Said I had two options hysterscopy or HSG
I decided to wait And asked for Femara. First month was unsuccessful but Month before we conceived but ended in our 4th m/c. I am now on my 2nd cycle on Femara. Almost finished my fertile week. 
Has anyone had a similar experience? 
Why can't we conceive but we were able to other people? 
We want a baby so bad. This year has been so tough. 
It's so easy for other people. 
Advise ? Tips? 
I'm desperate