James Brolin Gives Secret to Success in 25-Year Marriage to Barbra Streisand

James Brolin is giving the recipe for success in his 25-year-year marriage to the great Barbra Streisand -- getting surprisingly candid about what works ... and what doesn't!

We got the actor -- who's Josh Brolin's dad, and a well-established celeb in his own right -- while he was outside of the ABC Studios in NYC Wednesday ... where he was signing autographs and, apparently, feeling pretty chatty about his personal life.

Our photog asked if he had advice for people on how to keep a good thing going in the relationship department -- and James has an answer ... essentially, it amounts to therapy.

Check out how he describes it for himself ... JB says, sometimes, you need a third party to help break up the log jam a husband and wife might experience. So, in his experience, it makes sense to get somebody in on the conversation ... whether it's a pro or not.

There's a couple other X factors that'll keep a marriage together, according to James -- which amounts to a little give and take in picking your battles ... and shared waterworks.