He met Jane at an expressive arts school. She was there with her six children. He fell in love with her but assumed she had a husband. He could tell. She did.
For a few weeks Jane and her daughters didn't turn up and when they did they seemed sad. Looking at her Sherlock could tell that there had been a death in the family. Her wedding wing now looked dirty and she seemed to fiddle with it constantly. He realized it must have been her husband who had died. He told her he was very sorry about the death she was confused because she knew she hadn't told him about it. He explained how he knew and Jane smiled slightly at his clever ability.
She later fell in love with him also and they married. They had two children together, Ellen and Maddie and have been together since.