Slept with sister in law who is also married

It happened twice. We had one planned and other just happened. We obviously keep it to ourselves. But don’t think we will do it again. Guilt is just too heavy. We are obviously attracted to each other. We constantly flirt. But we love our family lives. And wouldn’t do anything to mess that up. But I will say she was a way better lay than wife. She is wild and we explored things we haven’t with our significant others. Part of me wants to continue. So does she. But we can’t get over guilt and the thought of us getting caught is very scary.