Hey, what should I do about someone I went on one date with and then broke things off with (for many reasons, including that I knew I wanted to switch to exclusively dating the other person I was at the time casually, and am now exclusively, dating) like a month and a half ago who keeps popping up? I broke things off over the phone, he called the next day and I didn't return his call, I ran into him a month later at an event which I attended with the person I'm dating (who I was really clearly with) and he was over-the-line touchy and flirty, and then he texted me again today to let me know that he'd still like to take me on a date. I feel bad because I know I've definitely been in situations where I've really liked someone I've had minimal contact with who then hasn't liked me back, but I've definitely never pursued someone I've felt that way about the way he's done. I feel like I've been pretty clear, and he's definitely clearly seen that I am dating someone else. I feel like it's definitely crossing a line for him to keep trying to pursue me, for many reasons, including that I've clearly told him no and also that I think it's pretty disrespectful to continue to pursue someone who is dating someone else.
Is it best just to ignore his attempts to contact me (they're very occasional) or to respond and tell him to stop?