Joshua Malina's Wife Melissa Merwin Files for Divorce

Joshua Malina's love story with wife Melissa Merwin has come to an end ... as the mother of his children has filed for divorce, TMZ has learned.

In new court documents obtained by TMZ ... Melissa filed to end her nearly 28-year marriage to "The West Wing" star, who she married back in December 1996. The docs are from Melissa's side ... so, this is her perspective on the whole breakup.

In the docs, Melissa cited "irreconcilable differences" as the reason for her split from the actor ... though she did not list a date of separation.

She is seeking for JM to pony up some spousal support ... but she isn't looking for child support or a custody agreement, as their 2 children are already grown.

Melissa's filing is pretty cut and dry for the most part ... and it appears she is seeking to amicably resolve this divorce with Joshua ... with minimal court intervention.

Joshua and Melissa's romance dates back to 1992, when the actor first met the costume designer via Melissa's sister Jennifer and former brother-in-law Timothy Busfield.

Joshua -- who is best known for his work on "Scandal," "Sports Night," and "The Big Bang Theory" -- has kept his marriage out of the spotlight for most of his career ... with Melissa rarely making an appearance on his social media accounts.