OP I am so sorry you are hurting, I feel like this is even harder to process than him having had the affair now and you finding out, because he has lied to you for so long. You had a gut feeling and I think you knew deep down, hence how you found out, as you needed to know the truth.
So you have had years of doubting him, and him lying to you.
Now, you know the truth (or some of it, as it is very possible he has not told you everything) so this is now new trauma which you need to process.
I have been where you are. I just knew and he denied it for a long time. Eventually I found out (not via him telling me either), and then my world fell apart as I now had the evidence. The thing that I found so fucking unfair is that I was just carrying on life as normal, trying to just get by, do right by everyone, then he comes along and destroyed my life forcing me to make the decision of how to move on. I think this is the part which I still cannot get over, the fact that his selfish behaviour caused ME to have to decide how to move forward. It would then be me telling him to leave, which destroys my dc lives, uprooting my home etc etc. So, I decided that we should try to make it work. I (is in only me) tried, for 6 years I tried. I cannot say that he tried just as much as he would not tell me the things I needed to know, I needed the info as the trust was gone. It just because too much after these years, and we are now divorced. But I see now that those 6 years of me trying, actually affected me in such a negative way. I had a breakdown, was admitted to the psych ward, was on medication etc etc. It just fucks with your head.
If I knew then what I knew now, I would have told him to leave there and then on finding out, so that I could properly decide how to move on without his pleading and sorrys in my face constantly. Which then turned to anger from his side as to being questioned often.
But every situation is different, I do get that. I do know a couple who have stayed together, but I do not know if they have the same deep rooted trust issues that I had.
It is just the unfairness of you now having to make some sort of decision, due to his behaviour.
You need time. Perhaps ask him to move out for a trial separation. Again, fucking unfair that its destroying your life, but you need space away from him to come to any sort of decision. 7 months is not a long time. The affair I am talking about happened 12 years ago, I have been divorced for years as well, but as you can tell by how emotive this post is, I don't think I will ever truly get over it. It is the lies more than anything else that did the most damage imo.
And yes, take his credit card and book yourself some therapy. On your own, most definitely not couples sessions.