nothing is wrong, well then why...

Checked for endometriosis I don't have it.
No cist on ovaries. Or abnormal cells.
I look completely fine down there....
So then why am I not getting pregnant?
And it's been over a year and two months of trying..
This doesn't make sense to me. I checked for everything I thought could be and I'm in the clear.
Does anybody else have this going on with them? Please explain this to me ( sigh) 
( my SO has two children)