The ex-couple's first property together -- which they purchased in 2018 for a steal at $13.4 million -- is back on the market anew ... only now, they're listing it for just under $18 million. The exact price is $17,995,000 ... for anyone who's a stickler the specifics.

Mind you ... this is quite the drop from what they were hoping for when they first tried selling this pad in 2022. At the time, their asking price was $21.9 million ... but they had no takers, so they dropped it down to $19.99 mil back in March of last year.

TS and KJ still weren't able to get rid of the pad -- and the listing ended up getting removed entirely around September ... but now, it's cropped up again, with a 10% markdown.

Whether it's $21M or $17M ... whoever ends up taking this off their hands is in for a whole lot of house -- it's got 7 bedrooms, 11 baths with over 9,000 square feet of living space.

In terms of perks, it's got a ton ... a private movie theater, a billiard room, a gym, a massage room, and, yes, a pool as well. Remember, this is Kylie and Travis' first home together -- but obviously, they're not together anymore ... so they don't really need this house in the mix.

Kylie's got several other properties in her portfolio ... Travis is doing just fine as well. 'Million Dollar Listing' stars Josh and Matt Altman of Douglas Elliman and Adam Rosenfeld of The Agency hold the listing.