Tmi question.!

Michelle • 27 years old Wifey & Momma of a 3 year old. Currently expecting #2 in July 2015
My hubby and I have a bet going on who is right.! 
The question can sperm (meaning hubby cumming inside you) cause ur cervix to thin. And cause a miscarriage.? 
I think yes! Because I've always read that at the end of ur pregnancy sperm can thin the cervix and help
Labor start. If that's true then why wouldn't that be a worry during pregnancy? He thinks it's false and that sperm is totally save and of course he's a guy and wants to saw sperm is even good for a women's health (including swallowing) lol 
Your thoughts ladies!