Hello Brett, doing texts and making phone calls by you or by them is completely different than living with someone, it does enable you not to respond if you don't want to, whereas if you are living together, then you could be forced to communicate with each other, something you may not want to do.
I do this with my ex and we do see each other, but we don't live together, this could be possible as we have both changed, but at the moment she is looking after an elderly person who has dementia.
If you are happy to talk through a text or speak to them by phone then there's no reason why this shouldn't continue, remember you do have the option of not continuing when an issue arises that you didn't agree on before.
If you are happy then do it.
Geoff.