Ben Affleck and Jennifer Lopez pulled the plug on a mansion they were trying to buy — but for good reason — ’cause the new one they want is way nicer … and twice as expensive.

Real estate sources tell TMZ … the married couple is currently in escrow for a massive property in the Pacific Palisades, the same neighborhood where they were just in escrow for another house … only to reverse course at the last minute, as we first reported Sunday.

This new crib is quite the palace … whereas the mansion they just bailed on was worth about $34 million, this one they now have their sights on is valued at a whopping $64M!

The price tag is certainly high, but it might be worth it when you consider everything it comes with — including 8 bedrooms, 11 baths and 16,000 sq. feet of a fortress on a 1.13-acre compound. Yeah … it’s humongous — and that’s not including everything else inside.

Ben and Jen’s would-be new home comes with an 800-square ft. gym, a professional media room, a game room, a spacious backyard and a resort-style pool/spa with a firepit area too. There’s a whole separate guest house, which has its own Japanese-style soaking tub.

And, don’t get us started on the views … of course, they’re canyon-side and to die for.

Mind you, this is the property that Bennifer recently visited in person … and our sources tell us they’ve been swinging by frequently to eyeball changes they might wanna make once the sale goes through. They do this often, BTW — even at the other PP house they nixed.

Oh, and if you’re wondering how Ben/Jen can afford such a pricey pad — beyond just being filthy rich — we have answers on that as well. Our sources say Jen’s famed Bel-Air estate, which has been on the market for a minute, is also now in escrow with a potential buyer for $39M.

Add on the fact Ben recently sold his own Pacific Palisades mansion for around $30 mil, and they’ve got plenty of money for the new crib.