to stay in Canada without valid visa does not preclude your basic right to love or marrriage.
write a sincere letter to visa officier to
apologize for your poor deicsion to stay on without visa, because you were young and sometimes do make decison on impulse, maybe be because you love canada too much, or love your lover too much and fearing losing him when away or any other reason convincing to arouse sympathy from whoever reads ur lettter.
address the officier just like a friend and seek help from him or her how you could win their trust again and what they needs from you to proove your marriage is real and genuine.
the tone of the letter should be pleasant and be a bit homour for your poor decision in the past and sincere for expecting help from officier