Difference betwen friends and lovers.....

Lovers often speak their love for each other to one another....

 Friends rarely speak of the friendship to one another, instead tending to accept 

it as a “given” and operate in it when together.

Lovers often express themselves physically and verbally face-to-face, 

absorbed in each other...

 Friends stand side-by-side, absorbed in some common interest, goal or philosophy.

Eros love is (healthily) between two, and only two. 

Friendship can increase in its enjoyment by the addition of two, 

three or more so long as the interest, goal or philosophy is somewhat the same as a common bond.

Friendship is born from “common panionship”, the discovery of common interest between acquaintances. Companionship / acquaintances are not necessarily friendships. 

Lovers seek for privacy. 

Friends pull from the herd in becoming friends buy would appreciate a 3rd, 4th or 5th party on the same terms.