Dean McDermott Says Divorce from Tori Spelling Was Long Time Coming

Dean McDermott's not letting his relationship woes slow him down, 'cause he's keeping it moving after Tori Spelling filed for divorce ... which he says was inevitable.

Check out this clip of Dean that was shot over the weekend -- on the heels of Tori filing -- and you'll see he's not really sweating it all that much, or so it seems. He's being interviewed by a pap as he gets into his car ... and is asked directly about the divorce.

Dean is looking cool as a cucumber ... as he reassures a pap he's doing good, despite everything going on. He calmly admits the decision to end things was a long time coming -- adding that despite the split ... things aren't bitter between him and TS.

Pretty interesting ... especially considering how long this split has been playing out.

Remember ... Tori dropped the divorce bombshell during her "misSPELLING" podcast, and while he seemed a bit shocked in the moment, DMD here comes across as the opposite.

Tori explained that Dean spilling intimate details about their sex life and such to the media was the final straw for her ... prompting her to make the swift move to the courthouse.