Reddit, how would you deal with a guy who steals all of your ideas?

This will be a tl;dr(ish) version.

Close friend of mine used to hook up with me a lot. She got a boyfriend at the end of summer but we hang out a lot still. She tried to make a move on me a couple weeks ago but stopped half way through and said it was wrong. Ever since she has been telling me how much she likes me and wants to break up with this other guy, and of course i'm a sucker so I'm kind of falling for it.

The problem lies with scumbag steve. He's found out about things that we used to do together such going to get food at the same restaurant every tuesday, and then sabotages them by copying them over the same dates.

Just recently he asked her to a concert to a band that I introduced her to awhile back and she fell in love with. The opening band is a band that i just showed her last week..

So this guy sees it as a perfect opportunity to go out of the city, get a hotel and pork her, off of my work.

I'm probably leaving a lot out, and sound like a dick. but I am just really irritated right now because he pulls garbage like this all the time and she can't see whats going on. So I feel like good times, and emotions that should be with me- he steals, and it pushes us farther away from being anything.

What would you guys advise?

Thanks..

EDIT:TL;DR: boyfriend forces my friend who cheats on him with me to tell him everything we do when we hanagout, and then he just copies all my originality/personality. Except, he always makes sure its out of town so he can get a hotel and fuck her while he's at using my ideas.