My best advice is that you have to feel it out. Generally, if you are responding emotionally to her messages then she is probably responding emotionally to yours. The key to leaving her wanting more is finding the high point of the emotional conversation. In other words, you need to keep an eye out for a text message that satisfy all three characteristics.
Here is the thing. You want to focus on you not only because this is healthy which is the main reason and you're putting yourself first but by putting yourself first he will want you more. There is a deep desire for people to be with someone that puts themselves first. I would not only follow his lead. Make sure you are not too available in the process and really schedule time for you. Then take control back a little bit so you can eventually see where this is headed.
This is absolutely no excuse for you to be cheated on. Your independence is important and if he wanted the attention he should have spoken to you about this before he cheated instead of cheating and then placing blame on you. This is narcissistic behavior and I encourage you to stay strong. If you need further help you can reach out to me for a private coaching session here so I can guide you towards working through this. https://www.apolloniaponti.com/private-coaching-2/
Getting an ex girlfriend back is probably not going to be done strictly through text messages. It will probably take conversations on the phone and in person to achieve that goal. So, I think it’s best if you manage your expectations when it comes to texting. Rather than viewing it as the “go to” tactic for getting her back the smarter way to approach it is to view it as a stepping stone to getting her back.
If a man is honest and tells you he does not want a relationship, then as a woman you should honor his truth in telling you this and take a moment to reflect and understand that you may need to pull away. Not to mention, if he also gives you the popular one-liner by saying, “I’m just seeing where things go,” proceed with caution. This is not a committed answer, so why would he want to commit to you? This is just an answer to lure you away from the truth in hopes to keep you around for what he is in search of pleasure and attention.