Question: I have nearly finished my book, it is about a group of high school friends who graduate and go on a cruise, and on this cruise they find their partners, I guess. There are two main characters, and the story flips from present to past. However, I'm worried that the romantic parts of my book may be a bit cheesy or over the top? Would that still be okay?
What you should do is visit the websites of various romance publishers, such as Harlequin, and check out their writing guidelines. Publishers put out many different lines of romance novels. Each line has its own set of guidelines because it is targeted to a different audience and set of tastes. Look for the lines that are closest to what you want to write (or have written).
This is especially important when it comes to sex. Some lines have no sex at all. Others have so much explicit sex they could be classified as erotica. And there are many levels in between. But an editor who's selecting titles for a hot and sweaty, forbidden love romance line won't be interested in a book with only a little pre-marital kissing, and vice versa
Similarly, there are romance lines catering to teens, new adults, middle-aged adults, seniors, etc.
There are lines catering to specific religious beliefs or cultural backgrounds. Christian romances, for example, don't have sex outside of marriage. Harlequin's Kimani lines are targeted to African-Americans.
And there are separate lines for crime romance, paranormal romance, suspense romance, etc.
The good news... Quite a few romance lines feature stories that some people would call "cheesy." You just have to know which line you are writing for.
It's a good idea to read a few books from the lines that sound promising, just to see what types of plots and concepts the readership enjoys. That will help you know if your book is a good fit.
If writing romance is your thing, you might also consider joining the Romance Writers of America. They provide a lot of help to emerging writers.