Just the Two of Us by Barbara Brooks

Novel follows the lives of three lesbians in the big city.
' Determined to make their love endure, they turned their backs on the world '

From the back:

At first there were 3... Then there were 2.

Connie... the sleek and sensuous redhead, cynical and shockproof, a specialist in catering to the coarse demands of jaded men as well as the secret needs of lonely young women.

Joanne... the angel-faced blonde, fragile and appealing, nuturing a neurotic jealousy that demanded a vicious and savage revenge.

Susan... a small-town brunette with big-city dreams, breathlessly eager and painfully naive, too young and innocent to cope with the evil forces that lurked behind the glittering tinsel of the neon jungle.