Do you think love can get 'expired'? Like someday it will be boring and dull? Does that mean they're not the one for us?
The "head over heels" feel will fade with time, but if you really love someone that won't stop you from being with them after that feeling have gone into the background IMO, and it should be possible to ignite those feelings during romantic moments still. (then again my relationship experiences have been few and awkward so I might not be much of a expert on this subject...)
Apparently the euphoric feeling only lasts a year or so. Hopefully to be replaced by a deeper connection.
It depends really. In some cases that feeling does die for people, other times though people spend their whole lives together.
