I don’t know how old you are (which always helps me give advice), but I’m going to guess that you’re old enough to understand how dating works. Men (and women) are free to date whomever they want to try and find the best possible person for themselves. If he’s interested in someone else, as you’re describing, it’s totally fair game for him to see if she’s a better match for him than you are. The two of you aren’t engaged, living together or married — you both have a responsibility to find the best possible Mr. or Ms. Right for yourselves.
That said, if you want to win a guy over, read Think & Date LIke A Man, [url]http://www.askapril.com/relationship-dating-advice/think-and-date-like-a-man.html[/url], so you understand how to attract and capture Mr. Right! You can buy the book on the link I’ve just given you where it’s an automatic download or you can get it on the websites for Barnes & Noble or Amazon.
Instead of just thinking, do something different instead of trying to give him boundaries (he already has a mother! 😉 ).
I hope that helps. Please follow me @AskAprilcom on Twitter.