I guess the risk is this....say he has a little tiff with OW last night. He's a bit mad at her. He thinks fondly of you. He texts you (is Jpeg still on the hook?) You text back. Yes she is. He and OW make up. Jpeg is forgotten for now....
If the above is what is happening (or something similar) you risk remaining - on the hook, plan B, back burner or whatever you want to call it - for a good while.
So, while it's evident he has feelings for you. I'm sure many of our WAS's do. What truly matters is taking significant action back towards the M. I don't think anything less than that (given the betrayal and ongoing R with OW) should really interest us. We should take it for what it is and move forward. Otherwise, we risk just being someone who participates in covert texting with someone else's boyfriend.
You've replied and that's fine. However, I would take it for what it (probably) is for now, and move solidly forward. If your H wants to catch up, he has more to do than this and for sure he knows where you are.
This isn't a 2x4 as such, but I would be wary of responding too warmly to temp checks like these.
