Hi, Didn't get a chance to get on the site last night... Don't think that all is lost. Don't think you should not have sent that text message. I don't think you should even ask yourself if you should have or not. You were mad and angry and that was that. And I don't blame you. I know in the midst of my H's A, his lies seemed worse than anything else that I knew was going on!
So it seems that your H probably has more contact with OW than you think, or that he's been letting on. But you've had a chance to DB so you're in a good position to decide what to do next. He was all set to come home. Why would he do that if the A was not over? Perhaps he really was/is trying to end it. If he does, it will not be good for the A. OW will not like that one bit.
But if you're not ready for that, if you need more time, if you need him to prove his fidelity and trustworthiness to you, then wait.
On the other hand, if he's serious about coming home, he's got some serious hoops to jump through (starting off with NC with OW). Such as, he'll write a NC letter and let you deliver it.
I say follow your heart (which may not be easy with the torrent of emotions that you're going through right now!).
