I know you would like to trust her. The problem is, people lie about the facts around affairs. Period. Your W is not going to be the sole exception, really.
The truth MAY emerge slowly and painfully IF you reconcile and W is fully committed to the M. Otherwise, psychologically, it simply will not be worth the emotional/legal expense for her to come clean. Nor, does it really matter if you don't reconcile. In that case, the problems in the R don't need to be worked out.
Trust yourself. You can't trust her on anything regarding OM right now.
