I would ask you to be cautious if you decide to start dating. Stop gap dating is dangerous as emotions are raw. I believe one should only date in our situation when we are prepared to go the distance with a new partner. If that is the case then you transfer DB from your XW to your new partner. Otherwise why date if you have no intention on D. Just be sure if you drop the rope that should w reach out you not react on instinct and go running back but evaluate what you want and not her.
Oh and btw in that situation you become a sort of WABF. See how complicated it is?
Just make sure it is worth it.
As for how to react with her texts, I am maybe a little radical. If my W has left 5 months ago, has a possible OM and reaches out to me with txt messages I am pro short replies. I mean really short.
I find it hard to differentiate between a w interested in what is happening with her H because she cares, to one just trying to make things smooth for her own concscious to one keeping her H on a string as a plan B. There are other actions and events as well as your own gut feeling when interacting that could determine this but in all honesty if in 5 months you only get txt with little to no calls then my guess is you are not on her shopping list.
I do not know your full situation but sometimes our happiness and W are going in opposite directions and we have to let go of one.