Legal Question in Family Law in Maryland

I assume you have a court order granting you legal custody. If that order also has a specific visitation schedule that limits the father to weekend visits, he's in violation and could be held in contempt for doing so. In that case I would suggest having your attorney write him a letter advising him that you do not agree to this unilateral expansion of visitation and will go to court to enforce the order if he continues to violate it. But if there is no specific visitation schedule or it is vague about this, you would have to get a court modification in order to enforce weekend-only visitation.