Not only can you “always get out and get a new and better thing”, but is encouraged (for economic gain) and glorified (to make people believe they can fill a “void”) by society. It is considered synonymous with success, and in this society being successful is the ONLY important thing.
I think the problem with sex (the bad part) and materialism is that not only are problems by itself, but they are hughly encouraged and accepted as normal. Drugs for example are also a problem but you also see campaigns and other forms of education to discourage them. Sex and materialism can be highly addictive but they dont come with any “warning label”
I think the pressure society puts on “success” (having lots of stuff) can be a huge burden on a marriage.
Also if you are brainwashed to get a “new and better thing” by materialism
and to see women (or men) as objects, you may just go ahead and do exactly that “get a new and better thing”