Dwyane Wade Baby

Exactly 9 months before Dwyane Wade's son was born (by a woman who's NOT his fiancee) ... Wade and Gabrielle Union were still acting like they were very much a couple ... and TMZ has the proof.

We broke the story ... Wade's baby mama Aja Metoyer gave birth to Dwyane's son Xavier on Nov. 10. Wade claims the two were on a "break" at the time.

But on February 5th (9 months before the birth), Gabrielle was Instagramming about Wade ... posting a photo of the NBA star cuddled up with her dog Sasha along with caption, "Sasha don't play when it comes to her man... 'Down to ride 'til the very end, it's me and my boyfriend.'"

A couple of days before that (on Feb. 1), Gabrielle posted a romantic photo of the couple together from a photo shoot for a "Flashback Friday."

Doesn't seem like a couple on a break ...

There's more ... on February 19th, Gabby posted another pic of Dwyane holding one of her scripts ... with the caption, "It takes a village to help an actress learn her lines... @dwyanewade takin a break from his Gatorade commercial to give me a line reading. Thanks coach :)"

The patter continues until April ... when Gabby stopped posting pics of Dwyane and started posting a bunch of sad cryptic quotes. One reads, "We cannot start over, but we can begin now, and make a new ending."

Another says, "Sometimes you have to get knocked down lower than you have ever been, to stand up taller than you ever were."

But on May 16, Wade returns to the picture ... with Union posting a photo of the couple, along with the caption, "I like this dude."

11:30 AM PT -- TMZ Sports has learned ... Aja's two other children were fathered by "Happy Endings" star Damon Wayans Jr. ... the son of "In Living Color" legend Damon Wayans (obviously).

We're told Damon is very involved in the children's lives.

TMZ Sports has obtained the birth certificate for Dwyane Wade's brand new son ... which shows the kid's name is Xavier Zechariah Wade ... and he was only born last month.

Of course, Wade recently acknowledged that he had a kid with a woman who isn't his fiancee Gabrielle Union. There are reports that Wade and Union were on a break when the child was conceived.

Now, we know the kid was born in Los Angeles on Nov. 10, 2013 ... just 6 weeks before Wade popped the question to Gabrielle, who he's been dating since 2009.

According to the birth certificate, Wade's baby mama is 30-year-old Aja Metoyer. The details of their relationship are basically unknown, except the obvious fact they have a kid together.

Aja has two other children.

Metoyer did not list Wade as the father on the birth certificate, but she did give the child Dwyane's last name.

Gabrielle Union -- the future Mrs. Dwyane Wade -- took her brand new million dollar 8.5 carat diamond ring out in public yesterday ... but not without some serious hired muscle to keep it safe.

Gabby and Ring arrived to the Staples Center in L.A. ... flanked by private security ... to watch their man dominate the Kobe Bryant-less Lakers.

Funny, Kobe knows a little something about expensive jewelry ... in fact, he may have bought the most expensive ring out of ALL the NBA players ($4 million) .. except his wasn't a "Will You Marry Me" diamond -- it was a "FORGIVE ME!" diamond.

Every kiss begins with ... an engagement ring that costs MORE THAN MOST PEOPLE MAKE THEIR WHOLE FRICKIN' LIVES -- if you're Gabrielle Union and Dwyane Wade, that is.

Dwyane popped the question Saturday night with an 8.5 carat cushion cut diamond ring (pictured below) made by go-to celeb jeweler Jason of Beverly Hills ... and TMZ has learned it goes for nearly 1 million bucks.

We're told Dwyane had been on the hunt for months for the stone of her dreams ... and his jeweler made 3 trips to Miami looking for the perfect jewel ... and third time was a charm.

Bravo.