Sleeping with brother in law

I’ve been sleeping with my Husband’s brother for the last 7 years. All 3 of our kids are his and not my husband’s. Please help me come up with a way to let him know without him divorcing me. I do not work and need his support. Plus his brother is a dead beat and wouldn’t support the kids. It I can’t keep this secret any longer, but I can’t lie I doubt I will stop sleeping with him. Nobody knows me like him.