What does this have to do with pregnancy?
Id have him ask a doctor....this really has nothing to do with pregnancy or anything close.
Medhelp has a erectile dysfunction forum! They might be able to help you!
Once in a while such failures are common, may be due to stress, tiredness etc, but, if it continues he need to consult a urologist. Vericose vein can affect fertility and testicular health, and inturn affect sexual health if not treated for long time.
That is the same thing that happened with me @BreyBreyy. SOmetime I get boners, sometimes they just take a break. I'd recommend your boyfired masturbate before sex with you and get turned on, so that he can deliver something in the bedroom for you.