Unfortunate to there that there is such misconducts in your field.
In general it is a very good idea to share your paper with someone else. Usually that only makes any research better. At times, PhD student may not receive the best advices from their advisor, because sometimes they may not see "the forest from the trees". In my own experience sharing research ideas and drafts with someone who is not directly into that topic usually leads to fresh ideas, comments and helps myself to think outside the box.
I think every researcher regardless of the level should aim to connect and network with different people in different disciplines in order to have reliably people around you and thus be able to easily discuss with research papers and ideas.
As said in the comments it is important to listen and take advices from your advisor, but I also recommend discussing with other people to get a different view.
Maybe you could leave some critical information out from your paper and then discuss of it in more theoretical level? Without all the critical information the risk of misconduct would be definitely smaller. Do you have contact outside your own discipline but still close to your topic? I see it very unlikely that they would copy your idea, since they do not have all the expertise in your topic. I also recommend discussing with your fellow PhD students. Again I see hardly any risk they would copy your idea. I am an optimist and yet would like to believe in collegiality. Most importantly, you would very unlikely lose anything else than just a short period of your personal time if your share ideas with your peers, even if they have anything relevant ideas.