I withdrew from ...well, pretty much everyone. I was nonparticipatory in social stuff, and lesser friends might have abandoned me.
For a good, long time, I just pulled back. It was so strange; I so badly needed love, and to feel valued, but actually feeling that love and care from friends hurt. It reminded me of what I was lacking in my marriage. I was so fragile, that I thought that even the gentlest of hugs would cause me to disintegrate.
And social interaction also required ....well, talking about it. And I was embarrassed, ashamed, humiliated. I believed what my X told me about myself and my worth....and I was messed up enough that I believed others would see that, too.
Oh, I was so wrong.
I am grateful beyond belief for good friends. I have not lost any---but I have learned something I never knew. (And here I was, thinking I knew everything.) I learned others can help me. This sounds like an odd revelation, but I was always that go-to person. Even as a child, my "role" was to be the fixer.
And I was so broken, I could not only help anyone else, but I could not help anyone else.
And when I became brave enough to say, "I need help," my GOD! My friends were so willing to offer it.
Honestly, this is one really good thing that came from infidelity: I learned something about repricocity that I'd never mastered before. It was an enormous gift. Just enormous.
I have been so blessed. I have learned that people really, really care about me. That they are willing to give me space, if I need it or---and this was really important---to drag me out of my bad place if I need it. (I have one friend, who I learned was cheated on in her long-ago marriage, who was especially wonderful about saying, "C'mon. Just a cup of coffee..." and gradually getting me back into the world. I can't express the gratitude I have for her.)
It's been very, very difficult for me to leave my self-isolation. My friends---many of whom I had no clue cared as much---have been pivotal to my recovery.
I don't have a million. But I have far more than I ever knew.
Now, X and I didn't really have many couples friends; those "shared" friendships were primarily the result of my engineering. I still have all those friends. I haven't perceived any fear of "contagion." (I think it helps that people know that X really is tremendously personality disordered---they feel pretty safe from that sort of thing.)
I've been so, so lucky. Despite the profound losses I've experienced due to my husband's infidelity, I have gained things I would not have, otherwise.