3:35 PM PT -- TMZ has obtained Colton's divorce docs, which don't list his and Jeff's date of separation for now ... but do cite irreconcilable differences. He's asking a judge to terminate spousal support for both of them. He also signals each will pay his own attorney's fees.

Colton Haynes and Jeff Leatham are officially headed to splitsville, and it's clear who pulled the plug on the relationship -- because Colton's filed for divorce.

The "Teen Wolf" star filed docs Tuesday in Los Angeles just 6 months after he married Jeff last October in a star-studded wedding in Palm Springs officiated by Kris Jenner.

TMZ broke the story ... Colton and Jeff broke up just last week. Colton later tweeted, "Jeff would never cheat. He is an amazing man. Please stop being mean to him."

It was a stunning move following Jeff's extravagant proposal in Cabo that included help from Cher. As we reported ... Jeff proposed in March 2017 and, just 4 days after their engagement, they were already talking about kids.