I lived with my college boyfriend and it was awful! We were a great couple before it, and had EVERYTHING going for us. Neither of us, had a lot of money and it was the worst thing I've ever done. We fought all the time about money, rent and groceries. And, while my Mom taught me all there was about being 'moral' and 'respecting myself' sometimes the pull from others can be so great you forget who you really are...it was heartbreaking to see what I had done, and let myself do.
By living together, the fun of college ended...the prospect of our forever was shattered and we grew up WAY before we needed to. I was only 20 years old, and thank God my Mom was there for me when it ended and I needed help with emotional support.
If I were you, as a Mom now, I would ask your daughter why she thinks she NEEDS to do this now? Is there something wrong with waiting until she's married? Have a chat with her and let her know that you love her and you hope she understands that you know she's an adult and has the right to make her own decisions but, she has her whole life ahead of her to make a home with someone. Why not wait when it can be YOUR OWN home and not someone else?
For me, I got caught up in the feelings of 'love' I didn't understand and couldn't process. My Mom was against the relationship to begin with, so I didn't feel like I had anyone to go to until it fell apart. My Mom tells me now, that she knows now that she did her best to enstill me with values and morals, and she wishes she had been more open to talking to me about the choice instead of building walls...
How long has she been with this boyfriend? Do you know the family?
I've learned a lot from my mistakes, and now I am much more careful about how freely I hand out my heart.