In reality vaginas are an open canal, and semen can also seep out of your bum if someone came inside you during anal sex. It would be more.
What normally happens after intercourse, is that a lot of the ejaculate does leak out. Some of it, however, remains in the back of the vagina (in the posterior.
But then out come the ovulation charts and the pressure to succeed, and sperm through 'flow-back' – where fluid comes out of the vagina.