Mary's hurt eye's strike him through the heart and he begs for her to believe him, he didn't mean to he hurt her honest he didn't but she shrinks away and he knows it is useless to try.
Carson steps forward grasping his arm and there's nothing Matthew can do but let Carson take him away from the biggest mistake he has ever made.
The sun shone brightly even through the rain and Matthew felt the happiest he had in a long time, Mary had agreed to marry him and everything was going to be perfect. Strolling through the garden was relaxing until Carson arrived; he brought a letter with him. Mary's smile faded and he wondered whom the letter was from, what could it possibly say. Her grasp let go of the letter and his answer flashed across the bottom of the page, love Lavinia.
Matthew could feel a bruise blooming underneath Carson's iron grip, but he knew he deserved it. Lavinia had decided to confess of the affair her and Matthew had embarked on months earlier, he knew the time was going to come, Lavinia had become restless and was guilt ridden during the last moments of the affair. He hoped Mary could understand that the affair was in the past and that he love for her had only blossomed because of it, he knew where his heart belonged now and he prayed that she could find in her heart to forgive and to be able to return the love that he so desperately felt for her.
As he was lead past the window he glanced outside once more and saw that Mary had been joined by her youngest sister Sybil, they were embraced with Mary's head bent close to Sybil's shoulder, the body language sending out clear signals of distress and Matthew knew without words spoken that only time could heal the fracture that had formed between them.
Mary had gone to strike him but had collapsed in the end, she fell only being caught in the end by Carson's strong arms. Matthew knew that he would have felt better had she struck him, so that he could have shared in some of the pain that was beginning to destroy her spirit, her fire was beginning to smoke and Matthew was really not sure of how much she could take.
He took the last few steps of the entrance hall and left Downton with a glance over his shoulder and a thin hope that the family could understand his actions, but that Mary most of all could understand and forgive him.