Search Results: mad or not interested

I think I made a mistake, I asked out a coworker of mine. But anyway, we've gone out twice and both dates were alright. She asked me to join her on a hike, but it felt like I was just there so she wasn't a third wheel.
I asked her out and she told me no because she already had another date scheduled. She then proceeded to tell me about the date the next day. Although we have two more dates planned, she's told me a lot about the other dates she's gone on and it's been making me mad.
I wanted to cancel our upcoming plans and not talk to her unless it was work related and go about my business.
When I talked to my dad, he said I should go to the events still, but at the same time slowly decrease my texts and calls and then after the 2nd date, don't ask her out or text her like I am interested anymore. He says she will wonder what happened and either show how much she cares or forget about me.
Which idea is better? Does it change anything?