Good question jara.

You know what I once read? Now I don't know the authenticity of this. But I do remember what I read.

Apparantly our brain produces (more of) hormones in the first 6 months of a relationship creating that warm fuzzy feeling and sense of attraction.

I don't think this means the relationship is meant to get any worse / better by any means after these 6 months.

I view it like this.

By 6 months you would know someone well enough, warts and all, and have formed a bond and love with this person and this drives the relationship forward positively in a healthy manner.

Just thought I'd put it out there. I found it interesting when I read it.