Is it ok to be dating a guy but just talking and texting another?

I'm dating this guy that I really like i known him for a year now, I want a relationship but I also want to take it slow because my last relationship was for 5 years. And it ending badly. But... Theirs another guy who also has my attention I like him but I see things in him that I don't like. Should I tell the guy that im dating what I'm doing?