Pitt left a perfectly solid companion(Anniston) for a well-established nut case(As early as '99, Jolie was known for French kissing her own brother in public, and by '01 was wearing vials of her second husband's blood), Smith is widely reported to be a gay man who married for the sake of his career, and Depp decided to wife up a then-hot piece of ass he'd had a fling with on set, rather than putting that sh-t behind him, once The Rum Diaries wrapped. Dunno much about Costner's dating life, nonetheless Brady married a super model, a demographic not typically renowned for their depth of thought and emotional sturdiness
While there are no guarantees in life, a lot of pain and suffering can be avoided or/and reduced, by simply being cagey as to whom one allows into their lives. This is true for both genders, and applies in more areas than just dating
Ex. Don't say "Yes" to a high-paying gig with someone who's maltreatment of their workforce has long been the stuff of legend. A fair amount of that lavish salary is likely to be spent on rectifying both the physical and psychiatric woes you end up with afterwards