Simply by paying attention to what's going on. If you KNOW the OW is in the picture, back away from him; don't be as accessible to him, things like that. Dance the dance for awhile to make him wonder what's going on with you. Get on with your life AS IF he's not in it; staying just out of reach of him. He'll close the gap when he's ready.
He might eventually ask you what's wrong, or he might not; depends upon how deep he's within his thought life, etc. You'll know when and if you need to confront him about OW, LA. If you see him clearly bouncing between you and her.
If she is fading from the picture, be friendly but vague, like, sometimes take his calls and sometimes not. You do NOT have to always answer his text messages unless it's life or death.
I take it he is supposed to be beginning to deal with OW withdrawal? Detach and distance from that. Don't get sucked up into his drama...it's not something you need to bring down your PMA.
As long as the OW was in the picture, I refused to have anything to do with my husband, and girl, I was angry about it. I told him to get rid of her; shouting like a possessed woman! LOL! And he knew I was angry! It was a couple of months after the bomb dropped on me; I was headed for a nervous breakdown and it seemed that OW was TOO much for me at that point in time.
It didn't look at first as if my husband was getting that I meant what I said, though the OW was supposedly "hidden" from me and he was trying to get rid of her, denying her existence to me....yet, she was pursuing the heck out of him, and I KNEW what was going on.
I just didn't want to be involved in a triangular affair of any sort, nor did I want to be used until another came along(which didn't happen, but I didn't know that). I nearly lost my marriage because of that confrontation....but I was SO angry..and STILL had to deal with him going through OW Withdrawal..the time he had to have to get her out of his head and heart. I won't kid you, I HATED him with every fiber of my being...and his anger was something to behold.
Don't let your husband put you into that kind of situation; it's detrimental to your self-respect; and you'll know when it happens..and I really hope it doesn't. I'm hoping OW will fade on out of the picture, and your husband will begin to deal with the withdrawal symptoms, getting past those, and hopefully begin connecting with you once again.
I hope this helps you.
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.
Get on with your life AS IF he's not in it; staying just out of reach of him. He'll close the gap when he's ready.