You are wrong to get it counsulted here.
Any intercourse with a married woman can not be established by medical examination only its habituality of recent past can be established by a medical examination. Other evidences like check of seman found on girl's body or cloths are also other factors but, struggle and force marks arround vegina are important in a case of rape only (along with the seman spots) but not in consensual s*x between two persons.
So if there is no direct evidence to prove it in way of photograph or admission by the parties themselves the consensual intercourse can not be established as always it is made in privacy and after much precautions by the parties involved. It is very hard to establish Adultery in the court also. So do not get fearful about the same but feeling guilty and shamed on its own wrongs is a human quality which is a always great punishment to human being.
It is enough if you feel it was a mistake and you are ashamed of cheating your husband.