Alexis Bellino is on her way to becoming single, though she didn't have a choice ... 'cause her husband filed for divorce.
According to docs, obtained by TMZ ... the former 'Real Housewives of OC' star's husband, Jim, filed legal docs on Thursday to end the marriage. He cites irreconcilable differences. They got married on April 16, 2005 and list "TBD" on their date of separation.
Jim asks for joint legal and physical custody of their 3 kids, but he wants her to pay spousal support. This will be her second divorce. Alexis -- who joined 'Real Housewives' in season 5, but left the show in 2013 -- married her college sweetheart in 2002, but divorced in 2004.