Courtney, who were you texting when he was so curious before? It seems like your GALing gets a reaction from him. I agree with Jeff, creating the illusion of a boyfriend is not how you want to play this. I think that instead you should create the illusion that you want nothing further to do with him. One of your GALing activities could be meeting some people to text!
I would just tell him that you know, and you dont appreciate it. I dont think that you should tell him that you wont share him, or live in an open marriage if you arent totally committed to that, and prepared to be firm about it. Setting boundaries that you cant be firm about dont do alot to make you look strong!
I guess I gave the wrong finger to the wrong man...