Sylvester Stallone and his wife are calling it quits, she's filed for divorce after 25 years of marriage ... and is accusing the actor of moving assets from marital funds.

Jennifer Flavin filed docs Friday in Florida ... unclear exactly why she decided to pull the plug on their marriage, but some fans started to sense trouble thanks to a recent tattoo coverup -- the "Rocky" star removed an image of Jennifer's face from his arm.

She also made clear ... she believes Sly is hiding marital assets. In the divorce docs, obtained by TMZ, she says, "Upon information and belief, the Husband has engaged in the intentional dissipation, depletion and/or waste of marital assets which has had an adverse economic impact on the marital estate. Pursuant to Section 61.075, Florida Statues, equity dictates that the Wife be compensated and made whole by receiving an unequal distribution of the marital assets in her favor. Moreover, the Husband should be enjoined from, selling, transferring, assigning, encumbering, or dissipating any assets during the pendency of proceedings."

Jennifer wants to restore her last name -- Flavin. She also wants a judge to put the brakes on Sly moving assets from the marital pot. Closer Weekly first reported the split.

Stallone used to have a portrait of Flavin on his bicep, but recently got it covered by an image of his late dog, and "Rocky" costar Butkus.

When asked about the reasoning behind covering the ink of Jennifer, Stallone's rep told Daily Mail, "Mr. Stallone intended to refresh the tattoo image of his wife Jennifer; however, the results were unsatisfactory and, unfortunately, unfixable."

What's more ... Jennifer took to Instagram to post a photo with the three daughters she and Sylvester share, with the caption, "These girls are my priority <3 nothing else matters. The 4 of us forever."

Jennifer and Sylvester got married in 1997