Blackmailed into Seduction

I have everything.
A successful, wealthy husband. A beautiful home. Financial security. But once, I cheated on my husband with a random guy from a coffee shop. It was a horrible decision, one with more consequences than I imagined. My friend Angela found out about my indiscretion, and now she wants me to let her have some action. And if I don't?

She'll tell my husband.
I was happy and didn't want my marriage to end. What else could I do? It would be my first lesbian experience, but would it be my last?