A dangerous type became my girlfriend

The female protagonist, Miyu, is your typical golddigger girl - she hooks up with guys, milk them for all they're worth, then dump them and move on to her next prey. Yuuki-kun, her latest target, seems to just be your typical nice guy that genuinely looks out for Miyu, completely oblivious of her intentions. However, something's different about him that makes Miyu unable to carry on her usual scheme...