The advice you've been given here is excellent advice; I don't think I can add much, if anything to what's been said.
From what I remember, OW Withdrawal comes after the affair is broken off, whether by WAS or by OW.
He will have to, during this time, process the affair and take the necessary time he needs to get her out of his heart and mind. It's really sticky during that time, as the least little push will get you punished emotionally if he doesn't decide to run away.....I made that mistake, and if I'd left it alone, he would have connected with me a little more quickly. We still slept in the same bed, and stuff, total rejection was awful...and my anger and pushing made it worse.
If you are already at a place of just standing by in case he needs you as a friend and just watching..you're doing well. Don't ask him any questions, I believe he will talk when he needs to talk.
The affair while it was going on- was like an addiction or band aid for the pain, keeping him from dealing with his issues. It is VERY possible another OW could come along..but that would only be if there's another opportunity. And, if you stay low key with him, letting him come to you; if you are there and available; he might attempt a connection with you. But keep your expectations to zero and below, because this might not happen until he gets out of OW Withdrawal. And that can take awhile.
Withdrawal can be scary when you're looking at them from the outside as they are looking within, and it's visible..the eyes look like a puppy dog's; and you think for a minute they've flipped out.
Rock bottom signs are quite clear when they happen..they will not take a bath, and neglect themselves, even to the point they don't brush their teeth OR comb their hair; this also can run in tandem with the depression that sets in. I'd seen this in my husband when he hit rock bottom during OW Withdrawal, and again when he was in Withdrawal going into Depression. He hit the bottom twice that I remember..creeping back out each time.
I made a great many mistakes during that time; I know what NOT to do...and that was and is NOT to do any pushing or questioning...just let it be; and allow him to take the lead in this. Don't change anything you're doing.
Just "Watch and Wait".
From what you've posted did your husband end the affair or did OW, not that it matters, I saw you said that your husband still tries to contact her for now...which tells me OW may have broken it off for whatever reason, and that might make a difference in his processing of the affair.
It was the other way around for me..my husband broke it off, and finally got rid of her for good after she harassed the daylights out of him. She never got to me; Caller ID was my best friend....I didn't answer the phone, nor would I allow him to convince me to get the number changed, though his reasoning kept changing by the hour until he finally gave up and stomped off, mad as the dickens. His actions had consequences, and I figured why should I allow him to skip out on something he kept lying about anyway..and why should I protect him? I refused to help him..and that probably was the best thing I could have done for him...she was in his face through the Caller ID, calling attention to his shame and his sin of adultery. So, I refused to change the number, and let him suffer, LOL!!
Yes, I can laugh about it..it was SO stupid what he did, but that didn't mean I didn't still love him or wasn't afraid at that time I'd lose him.
The thing is; I sounded judgemental about it..but I wasn't being that way...wrong is wrong..and there no way of making a wrong over into a right; if that makes sense. His shame increased as her pursuit increased for well over a month or so, then she began to back away; but he didn't pursue her back..and I'd been afraid of that. I'd backed off and allowed the pursuit of him to go on in the hopes that this would scare him so badly that it would NOT happen ever again.
I made it clear some months later after she was gone for good and he was STILL lying about it, this was a one shot deal..he wouldn't get another chance to do this to our marriage and me. Far as I know, it won't happen again. He tried to convince I didn't know what I was talking about, and I put it this way: "I know what I saw, and I know what I heard, if you can't tell the truth..then don't bring it up; I don't want to hear it. But I'm a smart one now...I know the signs, and if I see them again; you will be shown to the door, no questions asked." And I meant it.
There did, for me, come a time when he was confronted without the fear of him withdrawing himself from me...but the confrontation I spoke of above came MUCH later when he was a lot stronger..and things were different for us.
The bottom line is this: OW is the MLC'er's problem, not the LBS'. And the MLC'er is the only one who can get rid of OW when that time comes if and when it does..as I'm aware some affairs can go on as long as two years or even more.
Take care of yourself..as you are the one who is most important at this time, as always. Continue to work on who YOU want to be; while just watching and waiting to see what's going to happen next.
Take care.
Remember, as each person is different, every MLC/Transition is different..what works for one may not work for another. Most of the time it is trial and error for ALL involved.