why cant he cum ?

he has never had this problem. we are ttc for our rainbow baby. its being 4 months since we started ttc i ovulated yesterday . the past 2 days (yesterday and day before) we where having sex with good feelings but how ever he tries which ever position he could not come. i dont know y this happend any of u have any experience with this. on the 1st we had sex and he came in me ( we saw each other after a weak). please help i dont know where to post this so im posting it in couple of places. edit: gys he is not into sexy stuff i do oral usualy as a foreplay. he is a diffrent type he dose not have any thing for dressing sexy or any fantacies about sex( other than anal which i cant) should we see a doctor about it. if so then which kind of dr.