Why would an intelligent Ukrainian, reasonably well-off woman want to come and live in the UK?

She is an intelligent attractive Ukrainian woman with a good job and very loving family in Ukraine; she loves, and is proud of, her country. Why give all that up, to come and live in the UK and marry a man she met on the Internet and has corresponded with for two years? Why go down that route in the first place? What could be her motivation? What factors could be at play here?