The 44-year-old singer has been living apart from her husband since June and has started the divorce process, reported Daily Mirror.
"Nick and Mariah have the paperwork in place for the break-up. Both will not have to give away their fortunes, and will split very easily in legal terms," a source said.
"The one clause that is a problem is that he must not speak about Mariah or kiss and tell. If he does Mariah can come after him legally. Mariah has always been controlled about her personal life. Nick is a much more open book and could face troubles if he lets slip," it added.