Source: Bang Showbiz NewsDennis Quaid has filed for divorce less than two months after his wife Kimberly Buffington-Quaid announced they were separating and is seeking joint physical and legal custody of their twins.The 'G.I. Joe: The Rise of Cobra ' actor confirmed he is ending his marriage with his wife of eight years Kimberly Buffington-Quaid on Friday (30.11.12) just six weeks after she announced their legal separation.The actor - who was previously married to actresses Meg Ryan and P.J. Soles - has requested joint physical and legal custody of the couple's four-year-old twins Thomas and Zoe and has also offered to pay spousal support, according to People.com.Former real estate agent Kimberly originally filed for divorce in March because she said the marriage had "become insupportable because of discord or conflict of personalities." She later asked for their divorce to be put on hold in April to give them time to work on their marriage but then filed for a formal separation in October.A source connected with the couple revealed the reason for the renewed split was that "Kimberly is fed up with Dennis' cheating and wants out of the marriage. He's not a good husband." Dennis, 58, and Kimberley have already overcome a great deal, as their twins almost died shortly after birth because they were accidentally given a massive overdose of a drug at hospital.