Amanda, hello and welcome!
I think the thing about preseed is that it is friendly to sperm. It's not that it makes you get pregnant, but it is a lubricant that doesn't harm sperm.
The
Ovulation and TTC Tips slideshow may be helpful to you.
Good luck and let us know how you're doing,
Byroney
Hope is a thing with feathers / That perches in the soul, / And sings the tune without words / And never stops at all. - Emily Dickinson