That is a chemistry thing.
I myself feel it is very difficult to rebuild.
Once it has gone, it would take a lot to get it back.
For some men, they feel it is like going to eat the same food every single day.
For other men, they just go through the motion, to save the peace.
Some women reinvent themselves, but that takes a great deal of time and work.
It can work, and some have a makeover on face and body.They seem to feel it will bring back the romance, and in a lot of cases it does.