https://www.ncbi.nlm.nih.gov/pubmed/10706945FOR ONE FULL CUP OF SEMENA few of us (not many) here have a wife or girlfriend, so this could be good news to share
Semen is mostly water.(1) Semen also contains amino acids and protein, sugars such as fructose and glucose, minerals such as zinc and calcium, vitamin C, and a few other nutrients. (2) Sperm cells themselves make up less than one percent of semen* and are not present for men who have had a vasectomy. Semen is edible, and if swallowed, will travel down the esophagus and into the stomach, where it will be digested in the same way that food is.
Specific behaviors involving a man’s ejaculated semen may be considered erotic to some, but unappealing to others. Such behaviors may include ejaculating onto a partner’s face during sex (a motif in pornography commonly referred to as a “facial”), or into a partner’s mouth. In the latter case, which may arise during fellatio if the penis is not withdrawn from the mouth at the point of orgasm, the giving partner may choose to spit the semen out, or to swallow it.
The choice is ultimately a personal one, but with safe sex practices, communication with your partner, and experimentation, you may discover your own opinions about swallowing ejaculate.