You are probably right - - you can't talk someone into loving you... telling someone that you are needy is not an attractive thing. You are essentially telling them that their efforts to care for you are not enough. I would say this is likely to be a turn off for a Thai person.
For the most part, financial security is more important than romantic love... most Thai have lots of friends and family and don't have the needs for the type of connection that you have... In many ways, they are more practical.
How long have you been together? Are you part of the family? How much have you given out financially and emotionally? Good luck to you, but my guess, and only a guess, is that this cannot be resolved to your satisfaction.