It is okay, doctors recommend it. I would be careful though because sperm can cause contractions (happend to me) luckily they stopped them by giving me fluids. I would just take precaution love:)
Yes , having sex actually helps open the cervix so ots good to have sex helps your baby come quicker if u have alot of sex.
Yes it is perfectly fine. It is completely safe even at 40 Wks.