Unexplained Infertility

My husband and I have been ttc since May 2018. We have been tested and diagnosed with unexplained infertility. All tests have come back perfectly fine. We recently had an appointment with an re and she advised we should go straight to IVF. She tried to explain the low odds of us conceiving with IUI but she said since it’s cheaper she understands if we want to go that route first. She also said she would prescribe me letrozole if I wanted to try that. But again she said it’s highly unlikely that would work.

I see so many posts about how many try 3 rounds of IUI before moving onto IVF so I just don’t understand why she doesn’t want us to try that’s first since there are no found issues with us? Other than her just wanting us to empty our pockets for treatment?

I have a consultation with a different doctor next week for a second opinion. Any suggestions as to what questions I should ask or concerns I should have about my last drs suggestions?

I’d also like to make note of the tests I’ve done. 3day blood tests as well as genetic testing. Day 3 ultrasound. Hsg. And my husbands semen analysis as well as blood testing. My periods are super regular and I’ve used opks and seem to ovulate every month. Isn’t there testing that can be done to prove you are in fact ovulating though? As well as progesterone testing? Because I haven’t had those tests. Should I be concerned they haven’t tested me for these or are those tests only done when they have certain concerns?

Sorry for the long post but any advice would be greatly appreciated.