Hulk Hogan's Sex Tape Partner Heather Clem -- Taped Sex with MULTIPLE -

Hulk Hogan isn't the only guy who was caught on tape with Bubba the Love Sponge's former wife ... TMZ has learned there are multiple tapes ... with multiple men ... in the same exact bed.

TMZ has seen three additional sex tapes featuring Heather Clem with other men -- shot while she was married to Bubba -- and in one of the tapes, she even walks up to the camera to double-check that it's recording.

In the footage, she tells her mystery partner -- neither Bubba nor Hulk -- "Is this thing recording? Okay, not that I don't trust you but I will get in trouble if it doesn't."

The insinuation -- Heather and Bubba had some kind of agreement in which Heather was allowed to screw other men ... as long as she recorded it.

As for the other two new tapes -- they were both shot in the exact same style as the Hulk tape ... in Bubba's bedroom with an overhead surveillance-type camera. It's unclear if the two men in those tapes knew if they were being recorded.

But as we previously reported, both Bubba AND Heather were aware of the surveillance camera set-up in the bedroom -- and were captured on tape joking about selling the Hogan footage for big money.

We reached out to Heather and Bubba for comment -- no word back.