What should I do if I find that my husband frequently sends WeChat to my first lover? Should I talk to her first love?

You should talk to your husband about it. You should let your husband know that he is married. You shouldn't do that. If he still wants to have a good life with you, don't do this. You are his wife, and you can't tolerate a third party in the marriage. See if he will contact that woman again. Then we'll see what your husband did, whether he broke contact or hid and secretly sent it. If he goes bankrupt, it's a good life. If he still hides and secretly sends it, it's really a big problem. You should think it over.