I have three sisters, we are all total junkies for this genre. We’ve tried our hand at writing one of these supermarket lust books, but we can’t take it seriously enough to make it past the first chapter. It’s a good way to pass the time at the beach, and we’ve been doing it for years.
The first “grown-up” book I remember reading was “Captive Bride” by Johanna Lindsey.
The next was “Sweet Love, Bitter Love” by (I think) Anna James.
And then I discovered the mother of all bodice-rippin’ authors . . . Kathleen Woodiwiss.
Y'all need to try NaNoWriMo, "National Novel Writing Month". I believe it's in November. Some of the folks in the Hobbit Hole do it every year.