One very telling sign your ex is open to getting back together is the tone, content, depth and emotion in your conversations. They may not want to talk about how they feel about you or about getting back together, but if they are letting you on their joys, upsets, frustrations, stress, confusion, etc., on things happening in their lives or people they care about, this is a sign that they feel emotionally safe around you.
Feeling emotionally safe with you is a pre-requisite for getting back together.