BSG75 wrote:The things I have done have driven a lot of my Wife's friends away, and while I have none of my own, she misses them to the point of pining for them.
Is that what your wife is telling you?
People do not typically stay away from a friend only because of a partner. They agree to meet and maintain the friendship independent of the partner. They meet for lunch, they talk on the phone, they go shopping together, they do things together without you being around.
If your wife wants to be friends and maintain friendships and make new friendships, she could. It sounds like she has lost friends and you are being blamed.
Should I write them each a letter apologising for what I have done ?
Or should I leave well alone ?
You don't talk to her friends. They are not your friends. It is not your role to put yourself in the middle. Instead, you talk with your wife. Your wife can then turn around and pass along whatever apology to her friends. Your wife can reach out to her friends and arrange lunches, shopping, phone calls, etc. etc.