"把自己搭进去？"

She is already in! She has been in a happy relationship with him for 4+ years - does that not earn him a 2nd chance? It's just a chance I am talking about.
I agree with you all that she should ditch him if they just met online - no history whatsoever. Clearly they have deep feelings for each other, they share a good life so far. She can't just kick the guy to the curb as soon as she finds out that he has a problem.