It doesnt change a thing!
If you loved someone why would you sleep with another person right before you die? That doesnt happen.
She nearly lost her job, just because of their relationship. Nothing happened to him.
As for the marriage thing, i dont think that changes a thing, i think Kims one was worse. How was it that Rach found out again? Im pretty sure it took some time before she found out Kim and Kit had sex. Whereas Rach told him, days[?] after it happened. she could have left him for Hugh, who was going to give her everything she wanted, but she didnt. She stayed with Kim-very stupid of her.
When Rach wanted to have children, Kim didnt want to. When Kim found out that Kit was pregnant, Rach didnt leave him. She was always there for him.