“I was asked to be in a poly relationship. What’s the good and bad about it?”
You did not define the type of poly relationship you were asked to be in, so it’s hard to tell if I am answering the question you’re asking, but I will try my best.
Assuming that your partner is engaging in poly behavior and you are not (i.e. they are dating more than one person and you are only dating them) the benefits include: knowing that you are wanted as a partner and not merely filling some void that another person needs filled by having a significant other. You also know that every time they come to spend time with you is time they want to spend with you, not time that they feel they are required to spend with you. You know that if they are being open and honest with you about their existing partners and relationships, and open and honest about you with their existing partners, that they will likely be open and honest if they ever meet someone new that they are interested in. Poly people are less likely to cheat, because there is less need for cheating. That’s not to say they are immune to cheating, but it is less likely.
The drawbacks include: sharing. We have been conditioned to believe that one person should be the end-all-be-all of our romantic worlds, so we look for partners that fulfill that role. Initially people who are new to poly relationships struggle to break away from this way of thinking. However, if you are in a poly relationship, there will be times when your partner is unavailable to you because they are with a different partner. This creates tension, jealousy and hurt feelings. You need to be able to constructively communicate those feelings to your partner so that the two of you can work through those feelings. Do not expect your partner to change their behavior due to your feelings, because they won’t. However, your partner’s awareness of your feelings, and your ability to work through them (with or without your partner’s help) will strengthen your relationship.
If you feel that your relationship with your partner is not fulfilling because of their other relationship(s) I recommend you take a piece of paper and divide it into two columns. In column A write down everything you WANT out of a relationship. In column B write down everything you are GETTING out of this relationship. Look at the things in column A that are missing from column B and decide if those are “deal breakers”. If they are, end the relationship. If they are not, accept that you may never get them, and enjoy your relationship. (This works for monogamous relationships as well.)
If you have been asked to join an established couple in a relationship, the good is that you get two partners for the price of one. What you need to know, is that you are joining an ESTABLISHED relationship. They have ways of doing things and dealing with things that come up in their relationship. If their relationship is stable, the ways they deal with things that come up must work for them. Many times you will find yourself adjusting to them, rather than them adjusting to you. You may feel like you are losing yourself in the relationship. Communication is key at this point, and listening to them. Remember that in two person relationships the individuals involved tend to morph into a single unit. In a triad the same thing happens, everyone comes together to form a cohesive whole. Learn about the adjustments they are making to be in a relationship with you, and do not discount their adjustments as trivial. Sometimes this couple may need a “time out” from the new relationship to reconnect as a couple. This happens, just like you may need to spend one on one time with one or the other of the partners to reconnect with them. As your relationship grows with each of the partners and with them as couple, their established relationship strength will seep into their relationship with you, until there is no difference in any of the relationships.
Learn what they want out of a relationship with you, and make sure you express what you want out of a relationship with them, then make sure they are giving you what you want, and you are giving them what they want. You must communicate your wants, needs, and desires constructively in order to maintain the relationships. Remember: In a triad relationship, there are four relationships happening simultaneously, and you are actively involved in three of them. Those relationships are: The whole group, the established couple, you and one partner, you and the other partner. All four of these relationships need to be strong, or the entire relationship is going to fall apart. Remember, that in the beginning, you are the weakest link in this relationship, so make sure you are doing your part to keep all four of the relationships strong.