It might be just semantics, but it is a *triad* that you are proposing if you all intend to be sexual and in love with each other. I would suggest you look at thread tagged "secondary" as there are many issues that could come up.
I am thinking you are in a bit of NRE over all of this and that is fine, but preparing is really beneficial before hand so as to not confuse things. Precautionary meassures are better than fixing things when they go wrong.
Ya, alcohol and drugs of any kind might produce a one night stand. At least in my experience that is all they have produced. Not to mention they can lead to taking a toll on ones *self* I would suggest staying sober and aware of everything as you go. Better to not jump into sex and work on the relationship. You are looking for more than sex it seems and that is poly. Otherwise its more like swinging and having an open relationship. All good, but different. Poly is confusing enough as it is. Adding sex right away can make it more so.
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