We all regret decisions that make us uncomfortable, whenever you started doing it.

It's your choice in who you're getting art of, and if you don't like it, you don't have to keep doing or just basically scrap em if you don't wanna look at them.

It's all up to you, since you're the one that's getting it. You could easily change your characters' style and what you get of them. Get whatever you feel like with whoever, as long as you're happy, then that's good!

Well look at it this way. If you're regretting that you've tarnished the image of your characters, and that you'll never get their innocence back, look at Rule 34. If it exists, it can be turned lewd. If you use these characters in works that are wholesome and sfw, keep your original smut of them away from it, but never be too afraid; they can't stay innocent for long.

Look at american comics. The retcons, the reboots, Superman must've gotten killed like 100 times. Just make a new continuity with your character that doesn't involve them fucking. Or hell, write out the lewd parts from the story. Do a "cleaned up/abridged" version "directors cut" of the story. There's lots of ways to go about this.

Good advice, as always.
I'm not super worried about it cos my dumb OCs aint going anywhere, especially not anytime soon, just I dunno, I've been questioning dumb shit like this a lot lately.