Dirty secret

I haven’t told many people about my husbands infedility. Only three of my friends whom I know I can trust. No family know about it. Other really good trustworthy friends don’t know and I don’t know whether I’m doing the right thing by not sharing with them. I oddly feel a sense of protection over my hubby. I know he feels ashamed and I feel like I’m holding his dirty secret. One of my friends that knows all about us tells me that I should share the news with friends and family so that I can get the support I need. I keep thinking of another friend of mine that had her husband cheat and I could never quiet feel the same way about him again even when they reconciled. 
I feel guilty when my friends share with me their relationship issues. I feel a sense of disconnect. If I ever tell them how will they feel. Will they feel as though I didn’t trust them enough or didn’t think our friendship was worthy. Strange the things I think of sometimes.