In water, there exist several of me;
On paper, I'm even more aplenty;
And though I am a sign of love;
Not even one of me does anyone want. (edited)
What am I?
Edit: so I did not intend for this to happen, but it turns out there can be many answers that fit. I check-marked my intended answer but everyone technically is correct! Thanks all for expanding the creative interpretation of this riddle.