Neighbors

It isn't charity that drives her, though he sees it as such. She doesn't get joy in "being a pest" as he calls it (helping him with the kids, with the house). She didn't "force herself into his life" out of pity or from a sense of obligation or even to get a self-righteous 'high', as he has accused her of before.
No.
From the day he moved in next door with Thomas and Kate (and of how her heart went out to their childishly broken-hearted expressions) he had captivated her, surly attitude and all. She had seen (glimpsed really) the loneliness in his expression when he shoved her welcome back at her. She sees how hard he tries to connect with his children. She sees what he could be. The greatness he keeps hidden, buried; His pain has driven him deep inside behind a curt wall and a reclusive personality.
She is determined to draw him back out, to give him the gift of the world and the world the gift of him - as he was once, as he should be again. So, she will ignore the insults, ignore the hurt, and help him (force him) to deal with his loss and his love and keep moving on.
Even though it will probably not be with her.