The US pound-for-pound fighter is believed to have posted a sonogram photo on his Facebook and Instagram pages, claiming that he ended the relationship because she had an abortion.
According to TMZ, the post, which was eventually deleted, read: "The real reason me and Shantel Christine Jackson @missjackson broke up was because she got a abortion (sic), and I'm totally against killing babies. She killed our twin babies. #ShantelJackson#FloydMayweather#TheMoneyTeam#TMT."
The couple became engaged last year after dating for four years, but the engagement was called off in April.