You are correct. That rush cannot be sustained. But when the full-on rush fades, it is still possible to rekindle that flame on occasion to keep the excitement going inside an older MATURE LOVE Relationship/Marriage. However, if there is NEVER any inkling of the excitement or rush (regardless of how samll), 'some' people open themselves to finding it outside the marriage rather than looking deeper (which requires work) INSIDE the marriage. And the BIG RUSH of a new R is apples to oranges over the more familiar "inside the M" rush. BUT the BIG RUSH cannot be sustained, as we have agreed.

That is why Affairs break up so often and the Infidelity folks expose to push that effect.

An affair (or what is also sometimes referred to as MLC) is a drug addiction. Some are more susceptible than others. Like any addiction.