I once knew this woman that kept getting yeast infections. It seems that her husband was either fingering her anus and then her vagina without cleaning his fingers and he also had anal sex with her then put his penis if her vagina for a while afterwards, again without cleaning his cock.
As far as not coming in the vagina to keep from getting pregnant, you will get pregnant soon. Any juice that comes form the penis before he actually bust loose is enough to get you pregnant!! Use a condom, or other birth control if you don't want to get pregnant.