Yes a subpoena can be issued for your phone records which includes the text messages. Your attorney could object to them being introduced based upon a number of grounds, one of which would be what relevance would they have. However the answer would be that they could lead to other discoverable evidence.
I don't see what they could be used for in divorce as either party has the right to a divorce and fault is not required. (Unless you have a covenant marriage). The issue of fault only goes to permanent spousal support which only occurs after the divorce, and the required proof there is to show the one seeking support is free from fault, not that the other party is at fault.