Abnormal Wife by March Hastings

From the back:

She stopped at nothing for her kicks...

Marian was not willing to leave well enough alone. She could have lived comfortably in the suburbs with her husband, but she was bored and restless. With him, the marital bed was tedious and sex routine.

That's why Marian decided to give her sensuality free rein. She went on an expedition into Manhattan, cultivated bizarre friends - looked for unusual, sensual experiences - sought odd types of lovers who would stop at nothing...