Questions about competing for a girl?

Guys, gals, so I have an odd situation happening and am just looking for advice from both sides. For a while now I was up north (near Canada) and this girl lives way down south. We've known each other for a long time and have dated over 10 years ago. We decided to take another shot. I believe she is worth the work. However with that being said, she's also been talking to another guy which I didn't know about until I uprooted my life and moved 1800 miles away to be with her. The very next day she started acting like I was nothing and she was all about this other guy which she didn't say anything about me to until the day I arrived. She hasn't been out of a relationship for that long maybe 6 months or so. Personally I feel like she is getting close to the other guy because he is friends with her ex. However she and I live together and she acts like we are in a relationship without all the mushy love stuff. If she's worth it should I play the game and compete or turn my back and ignore all the games? When I was still up north she and I would text everyday, talked on the phone once in a while. It honestly feels like she went to this guy because he is close to her ex.
Questions about competing for a girl?
Updates
1 y
With all this advice, I have decided to jump ship, cut ties, and start a new fresh life away from this girl. Thank you to everyone who responded.
Questions about competing for a girl?
Post Opinion