EXCLUSIVE

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.