A lot of authors take the concept of originality too seriously: they stress over it constantly even when they have fun ideas.
A guy on facebook was talking about an idea he wanted to write that he felt might be too cliche: in the far future a guy is sent on a mission to destroy a terrible new superweapon. He finds the weapon, and realizes it’s a lady, and falls in love instead of destroying it.
Now, I used to watch an anime OVA called El Hazard in the 90s, which involved something similar: a guy falling for a semi-robotic harbinger of the apocalypse which also happens to be lonely and confused. It was pretty fun, annoying anime tropes and rampant fanservice notwithstanding. Who wouldn’t like a Boy Meets Killer Robot story? It’s a cute premise and the sex is bound to be weird as shit.
The whole fun of writing is taking a well-worn premise and putting a new spin on it to see what happens. I wrote a love story myself recently (well, it was supposed to be a humorous supernatural adventure, but the romance sorta dominated it) called The Amityville Nuisance.

Boy meets medusa, boy befriends medusa, boy and medusa have frustrating off-and-on relationship while going on adventures in the occult. On the surface it’s a pretty standard trope — the boyfriend-girlfriend adventurer pair — but the mythological creature angle makes it interesting. How would a medusa adapt to modern times? They have image issues, so of course they would only wear the swankiest of outfits, and would definitely style their snake-hair into something posh (at the expense of the poor snakes, who hopefully don’t mind so much). And besides humanizing them as much as possible, how does one convincingly make a snake-haired demoness alluring? Probably not that hard this day and age, with all the weird shit on the internet. They’ve already got an anime or three about this very subject. Never would have thought to have a lamia wear a denim skirt.

I guess my point is, it doesn’t matter how original the story is, as long as you tell it well. And also that romances are stale unless they involve a monster babe or some other element of weirdness.
I’m getting sidetracked again. There is only one story: The Journey, with its call to adventure, occasional refusal of the call, then rising action, climax, and denoument. What matters is HOW you tell that story. If you’re worried about your work being too cliche, take it in a weird direction and see what happens. A cliched story about “knight slays dragon” becomes way more interesting if he has sex with it instead, and has a half-dragon kid who struggles to fit into regular society (thanks again, anime).
And if you think your writing isn’t good enough, you’re doing something right. The only people who assume they have no room for improvement are reality TV stars. Do you wanna be a reality TV star?
Don’t answer that. Just keep writing, and keep asking questions.
This has been another PSA from a random know-it-all on the internet, who happens to have lots of good books on the market (only some of which are about inter-species dating, I promise).