Do NOTHING. If you have to chase him then he's either not that into you or he's seeing another/several other women and doesn't have time to nurture anything with you the way a man that wasn't dawging around would have.
You've contacted him last... now it's time for him to contact you. If you "want to take it slow" and he doesn't respond to you after you've said that then he was likely just looking for sex and not wanting to be "taking it slow" at all.
Its best you quickly find out about men like him so don't chase him.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion