Sean Walsh reckoned that their relationship was almost over so he didn't think it was a big thing to kiss someone else's wife on a programme where he worked with her husband. After RH did a very public interview about him and his lies, she learned about other affairs he'd had.
She felt publicly and privately humiliated. If she wanted and was able to male money out if it, I don't blame her.
However, although Seann seems a bit self-pitying and self-absorbed, I think he's coming across as OK. Although calling Owen very wise and smart does make me wonder a bit!