Richard Burton had an insatiable appetite for sex: he reportedly slept with 2,500 women

The book And God Created Burton by Tom Rubython says: : “The actor from the Welsh valleys was continually unfaithful to both his wives (Sybil burton and Eliabeth Taylor).  In Burton’s heyday (between 1947 and 1975) he made love to at least one new woman every other day, with the total tally reaching around 2,500.” It helped, too, that he had a quick wit, charm and a total lack of inhibition when under the influence of alcohol — which was most of the time. He had no shame, either: even the wives of friends, like Jean Simmons, were fair game.”
“So how are we to account for his astounding one-man rampage through the female sex?  The first thing to be said is that his motivation was quite simple: until his late 40s, Burton had an insatiable appetite for sex. He didn’t need to love the woman he was seducing, or to be loved by her; nor had he any desire to possess her.  If she was willing, he was happy to do the deed anywhere: a dressing-room sofa, a vacant room in a pub, a garden bench, or even — if his wife was out — the marital bed. Often, he never even knew his lover’s name.”
“Women were drawn to him as if by magnetic force. (When he was starring  ) “on Broadway, he energetically worked his way through most of the 20 girls in the chorus of Camelot.  The good natured chorus girls, fully aware of what he was doing, used to manipulate the lyrics in one of their songs — “I wonder what the King is doing tonight” — to sound surprisingly like: “I wonder who the King is sc***ing tonight.”
Straight from Camelot, Burton flew to Rome for the making of  the film Cleopatra, where he was soon in the throes of a tumultuous affair with Elizabeth Taylor….Finally pinned down by a woman who had a chance of holding him in check, the great Welsh lothario ceased his extracurricular activities. For a while.  Aware of his weakness, Taylor had warned him from the start of their marriage in 1964 that she had zero tolerance for infidelity. But even she couldn’t stop him returning to his old tricks. 
“As the world knows, the couple divorced and then remarried 16 months later — but their reunion was short lived.  Burton delivered the death blow to their second marriage  by having an affair with the model Suzy Hunt.  As far as anyone knows, he was faithful to his two last wives — Suzy Hunt  followed by Sally Hay — but that was because, by his 50th birthday, he’d simply run out of energy. Burned out by a life of debauchery, he was forced to give up his favourite hobby. But it had certainly been a good run while it lasted.”