No one whose only connection to you is by marriage to a blood relative of yours is legally related to you in any way. They are no different than a person on the street from a legal stand point. So there would be no incest. I'm not 100% sure, but I think even if it was your aunt's second cousin, which would also be your parent's second cousin, and would be your second cousin once removed, a relationship between you would be distant enough not to be incest under the law.
