In short, cheating is a non-consensual affair in which the partner does not agree with their counterpart engaging in another intimate relationship. Whereas polyamorous (not to be confused with polygamy, yes, there is a difference) is where a couple consensually and consistently has more than one partner that is equal in the relationship. That is the difference in a nutshell.

What you need to know:
1. Do not assume you or your partner is into this.
2. Talk, at length, beforehand. Take the time to speak on every aspect
-bedroom arrangement
-gender of third
-boundaries-if at all
-long-term or short-term
-communication, communication, communication
-what you will tell your neighbors
-Is this legal in your state, area, country?

This is just a few things to speak to your partner about before walking flown this path for sure. If you feel like you are being convinced or coerced, you do not have to consent, state your boundary and be willing to leave if it continues. Spread love!

With Love