Looking out for gold diggers

I recently watched the Tech Lead YT videos on the danger a spouse can pose to the money you bring into the relationship. He mentioned that a gold digger can drain your finances unfairly, even if you diligently purchase her gifts and take her to fancy dinner. What are the classic signs of gold digger? My wife is always asking for money, with unclear ways she is spending such as “school supplies” and “food.” Recently she was crying and I gave her a diamond necklace hoping to make it stop... was this wrong? Was it a trap? I feel I have done everything right and followed all the good advice to increase my TC and get a 10 for a wife, from leetcode prep to PUA technique... but now I am concerned I did something wrong and now I am married to someone after my money. Please help Blind, this is very stressful now