He didn't get how people moved on right away quick to replace an old love. It's puzzling for him. He knew married people who go divorced things are not what they appear. In a loveless relationship where cheating ia allowed. Why would anyone want to share their loved one. Before they'd fight for one another. Now they gave up on what they had.
He said he loved her and ahe was quick to replace him. She loved him but he didn't feel the same way back. He didn't force it and things didn't feel right or natural. He knew her secrets she asked why he never tried. He never knew it was an option or if the thought crossed his mind.