I assume you mean that you and your estranged spouse have two children together, not you and your male friend, correct? Your husband could have you followed by a private investigator to get proof that you are more than friends. He could also have witnesses testify against you stating they have seen you with this male friend and that you are together. Finally, he could subpoena your friend and either depose him or have him testify in court under oath--then your friend would have to answer directly whether you are sleeping with him. Adultery can be tricky to prove in most cases. Why won't you and your husband agree to go forward on the no-fault grounds in MD?
It is not easy to prove adultery and, in many cases, pointless. You were separated for more than 12 months and both can file for divorce based on voluntary separation, so it is hard to see why he is claiming adultery. It is hard for me to imagine that a Frederick county judge would care about adultery committed after the separation.
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