Well honey, as someone once said "it ain't over 'till it's over". There are only two possibilities that I can imagine.
1)He is still keeping information from you.
2)He really is having a mid-life crisis.
I hope it's #2.
Let's assume it is. This is the second time he alluded to feeling like a jerk. You need to get him to tell you more about this. As I said before, you are the one who is going to have to do the heavy lifting in this relationship - but don't fall for that "I can't talk about my feelings" nonsense, it sounded like he was doing OK under your skilful questioning.
No. I would not give up on him just yet - if you ever get through this, he will get on his knees and thank you, but that is for the future...
One thing you need to watch out for is what someone once called "advance-retard" this means that sometimes you can plunge in and get him to open up - lie on his bed and talk. But as soon as you sense that he is feeling interfered with, you must back off - Let him seek you for chats. Then when he has settled down you can increase your actions. It's so easy for me to say this of course, it's very hard to implement it if you are desperate to save your marriage.
One thing though is golden: PLAY FOR TIME. Do not move out. Pretend you are still looking if you think it will help, but make sure that you don't actually find anywhere suitable! It's amazing how hard it can be to find accommodation these days
My only worry is that you said in another thread that he shared a hotel room with a work collogue - is she the one he texted? In a way it does not matter what happened before if you are going to forgive him anyway, as long as you are sure nothing is happening now.