Most men ejaculate daily. This is the bodies way of getting rid of old sperm and making room for new fresh ones ready to get a woman pregnant. Women do the same thing so as to clean the lining of the uterus walls and to stay horny so that she'll be ready when the right male comes along. Since people are having sex on a daily basis, sex is happening all the time. The mail difference between a man having sex with himself or a partner is mostly location.
Sex is life and all life, with the exception of viruses and some plants, comes from sex.
If we humans didn't have the sex drives we have the human race would have become extinct thousands of years ago. Our very existence depends on the kind of sexual urges that President Clinton is experiencing. If it wasn't for that, none of us would be here moralizing about it. A lot of us look down our nose at Bill Clinton as if he's beneath us. I'll bet he can't answer the question about why he did it any more that any one of us can answer the question as to why we masturbate.