Re: Sada Suhaagan Raho!
Is it a bad thing?
You are reading too deep into the dark, bleak and sinister connotations attached with the saying, and relying too much on the burden of history. In actual fact, wishing someone a long and happy matrimonial life would be considered a very positive comment in all societies and cultures. People who are happily married and cannot fathom the thought of ever living with their partner will definitely take this expression as a dua, and perhaps ask for more of it.