Mavis by Justin Kent

From the back:

How does a girl know whether or not she is a lesbian?

Probably the question never would have occurred to Mavis Harris if she had not wanted to help Tom, her husband. But to get him the business backing he needed, she deliberately yielded to the twisted desires of Louise Smythe - who had access to influence and money.

Then, more and more, Tom neglected his wife for his business. Worse, he began visiting motels with pretty Gloria Haynes. Everything Mavis had once depended on Tom for she now had to get from the artful Louise - and did!

Could Mavis ever free herself from Louise's kind of love? Or would she become an incorrigible lesbian? To find out, Mavis would have to throw the other two women at each other, thus releasing Toomfor herself... but did she want to?

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beautiful and unhappily married Mavis has a dalliance with another woman.