I don't think telling someone NOT to marry the person they feel in love with every works and neither does the reason why. Denial and justification will always be against that effort.
I told a good friend of mine NOT to marry the guy she had been crying over and complaining about for 2 year. The reasons, the guy drank to much, the guy got physcially with her several times. The cheated on her often. Guess what, she married him and made the decided not to be friends with me anymore.
I tried to talk to my brother about the woman he was planning on marrying who obviously had a drinking problem, guess what, he married her anyway.
Today, my friend is divorced, she feels embarrassed how she treated me in order to cling on to him. I am cautiously and ever so slowly rebuilding that friendship.
Today, my brother is in the middle of a nasty divorce, it took him 7 years to see what me, my ex, her mother, her brother and her aunt all saw and attempted to warn him about prior to marrying her.
People need to experience for themselves what they need to experience in life and make their own decision accordingly.
We need to make our own decision accordingly on how we will address being triggered by someone else's drinking. We basically have 2 choices, learn to deal with our triggers in being around them or chose not to be around them at all.