At the beginning of the year, I sent an email to my former advisor to ask him for advice on PhD topics. I sent him several ideas, one of them was a four pages research proposal (with methodology and sources) on one of the topics. However, over the course of my research, I discovered this topic might be difficult to research because of foreign languages, so I told my advisor I put it aside. I had other research ideas but I realized all of them are even more difficult to work on.
Nevertheless, I pursued my research on the first topic and discovered that plenty sources were available in English, sufficiently enough that I could work on. At the same time, I have discovered that a less-advanced student - still doing her master - was working on a very similar topic for her MA since the beginning of the year (she is at the same institution).
I am afraid my advisor sent her the idea since I told him I put it aside because of language issues. I suspect this because we didn’t have a good relationship (I got a very good grade for my MA, but he has a very difficult personality. He only supervised seven people for PhD in 20 years and one of his students switched advisor), but due to of Covid, I could not meet other professors. That is why I wrote to him nevertheless. I know he also shared my initial idea with my co-advisor working at a different institution (who is working in the same field so even her can give it to someone else) in an email because I was in CCd.
I would really like to work on this topic for myPhD - I used the same methodology for my MA but the topic is different - but I am afraid I can't it anymore. I also applied to another PhD abroad without telling him (only my co-advisor, who advises me to apply and recommended me for it) but the topic I would work on is not interesting me and there are funding issues.
What can I do ? Since I told him I put it aside due to foreign languages, did he has the right to give it to someone else ? Did he was not supposed to protect my ideas as he was my advisor for 2 years? Can I send him an email to tell him without looking like I am the problem? (I guess it is normal for students to doubt between different PhD ideas).