Thai women like a close family life. It follows that they may not be very understanding of men-only gatherings too often. They may perceive any other woman in your life, however harmless the relationship, as a potential threat. As a Westerner, you may find your Thai wife's close links with her family a little suffocating. You may find it difficult to adjust to there always being other members of her family in the house.
Thai women make excellent wives and are frugal and hard-working.
From the allowance you give her, she will see nothing wrong in putting aside a certain sum each month and not informing you about it. But this can be misinterpreted if one does not understand the rationale. Because you have joined her family, as she perceives it, not started a new one as you , a Westerner perceive it, you must discuss very carefully beforehand how you are going to react to requests from her for help for her family. My way was to give a present of money to my wife's mother before the marriage and make it courteously plain, through my wife, that my circumstances did not permit regular calls for my assistance. To have refused would have been considered very bad.