Reports state that former British Olympic equestrian Mark Phillips, who married Princess Anne, has had a complicated personal history that includes allegations of infidelity. According to the accounts, the relationship between Phillips and Princess Anne is described as being troubled by cheating on both sides soon after their marriage. One source also refers to claims that Phillips fathered a child outside the marriage and later had further issues during a second marriage. The same reporting adds that Phillips, now reported to be 77, is said to have found a new relationship. The articles characterize the earlier years of Phillips’ marriage as marked by mutual unfaithfulness, while providing limited additional detail beyond the broad claims. No independent verification or specific documentary evidence is included in the provided excerpts. Overall, the sources focus on the reported pattern of infidelity in Phillips’ earlier marriages and the later development that he is again in a relationship.