Directly said, I can't forgive Mary for her affair with Condé. The first time I watched the series I felt different, I believed she couldn't control her feelings towards him, and considered what she had been through, and was truly happy for Francis and Mary after their relationship was once again happy and the lover in the past. It is now the second time I'm watching it, I've grown more attached to the characters, and it hurts worst to see such betrayal. I now even think it was possible that Mary loved Condé more than Francis. She explicitly said she would do anything for him, told him he had his full, strong heart. It was not about her recovery anymore, it was all about her, his lover, and their happiness. Mary risked her country and life by sleeping with him, she could have ended up pregnant and killed for treason or even face disagreement by her own nobles and people in Scotland. Mary always said she and her country were one and the same, putting her duty before her marriage or herself, but not with Louis. While Francis would have given not only his throne, power, and freedom, not to mention he did give his life fighting for her despite the killers wanted to kill Mary, but also his family's safety and line.
True love never fades and yet Mary caused so much pain to Francis while supposedly having at least a bit of love for him. She did kill Condé, but I would say it was because she finally saw the risks. I know Francis also betrayed her by sending the duke of Guise's army to France instead of Scotland, but he thought he was doing the right thing and also betrayed her with Lola. His argument is valid, he thought he would never see her again and was hurt by her betrayal, they were not even compromised then. Narcisse's niece was a one night thing, he had almost completely lost hope and was devastated by Mary's actions. I can't believe that after she betrayed Francis and France so many times, risked so much, and loved Louis so passionately she could return to Francis as if not much had happened and doubt her love was truly genuine.