OK. Warm turkey? 
What I said is that keeping the relationship with him while she is being married to someone else without informing to her future husband the ‘nature’ of relationship is potentially very harmful.
People who smoke cigarette over so many years consider cigarette to be their ‘friend’ or ‘companion’. At some point they need to quit cold turkey style! The best way to stop. Otherwise there is a chance of relapse.
OK this does not mean the guy friend is a cigarette 
but he is an addiction for her right?
Any such person should work hard to build close relation with the spouse rather than worrying about ‘old friends’.