Adam was silent a little while, and then said, "It was very cutting when we first saw one another. He'd never heard about poor Hetty till Mr. Irwine met him in London, for the letters missed him on his journey. The first thing he said to me, when we'd got hold o' one another's hands was, 'I could never do anything for her, Adam—she lived long enough for all the suffering—and I'd thought so of the time when I might do something for her. But you told me the truth when you said to me once, "There's a sort of wrong that can never be made up for."'"
"Why, there's Mr. and Mrs. Poyser coming in at the yard gate," said Seth.
"So there is," said Dinah. "Run, Lisbeth, run to meet Aunt Poyser. Come in, Adam, and rest; it has been a hard day for thee."
Yeah, it has been a hard day for Adam. Shucks, it's been a hard book. Dude deserves a rest.
Although Adam gets his fairytale ending (wife, kiddos, weird brother/manservant), it's all tinged with sadness. We end this novel with Adam reminiscing about his meeting with Arthur, and Arthur coming to the super-uber-duper depressing realization that "There's a sort of wrong that can never be made up for." Ugh.
Then Seth, a.k.a. Friendzone Bro, changes the subject abruptly and says, essentially "Ooh! Neighbors! Looky there!" And gentle Dinah tells Adam to take a load off. This ending is both a) bizarrely anticlimactic—really, they're dropping a serious subject like Arthur for the sake of some neighbors? and b) totally realistic—they're dropping a serious subject like Arthur for the sake of some neighbors.
Because that's what Eliot does: reality. That's her dang wheelhouse. She's showing us normal life—sometimes you have to put old wounds on hold because some people are coming by for tea (or whatever British people do besides drink tea). Adam has a happy life at the end, but it's tempered with sadness. He has baggage. He's tired. He's got stuff on his mind. Because that's the way life is, dagnabbit.
You don't get a fairytale ending. Ever. But if you're lucky, you get an ending like Adam's: someone lovingly telling you that you need to have a lie-down, because you deserve it after all you've been through.