They say Love Is Blind. This is true.

During the initial early stages of a relationship (6 months to 2 years) your body will reward your experience with dopamine. This is the addictive part of a relationship where your partner can seemingly do no wrong and all their flaws are hidden. This is 'Love' as people refer to.

After this time, the glow fades and reality kicks in. Your partner's flaws become noticeable and your attraction to them lessens, and your want to sleep with them decreases.

If this is expected to happen inevitably (which all experts agree will) then what is the point in trying to sustain a relationship beyond the honeymoon phase when you can get the best of a partner elsewhere for a limited time once again?

Women are more in need of chasing the new relationship high than men are. This is why most relationships do not last longer than 2 years.

The honeymoon phase IS the relationship. Once that ends, you just have two people who get on relatively well, but don't have the same level of attraction to one another as before and ultimately, the relationship is headed south hereon in.