Most Helpful Girl
Sounds like she likes you but that attraction is gone. Take break from her for a bit and go on some dates, get down the gym etc. As soon as she see's you getting attention fom other women she'll see you as more of a challenge and you'll go up in how she percieves you.
Most Helpful Guy
Working out and focusing on you is good 2 more things you need to do. You don't have to ignore her, but mirror how she is acting. If she's not attempting to start or even continue a conversation then you need to do the same with her. Don't go out of your way for her.
Second, even if you don't feel like it you need to go out with other women. To get you back in the swing of things and to realize that women still find you appealing. Don't do this to make your ex jealous. Do this for you. She doesn't need to know you're going out with other women and honestly she doesn't have a right to know.
Feel free to not answer all of her texts.