I’m starting to think poly isn’t for me… wanted your advice on it. I’ve been with my SO for about 2 years now. They’re amazing and my world. Their SO is really nice too. But since we’ve come out to our families… his SO family hates me and thinks I’m going to ruin their lives. My SO’s family likes me but I overheard them talking about how I’m temporary because their child is just going through things… it just hurts to be like labeled as not real by so many. I’m not a bad person…

It’s up to you to decide whether this is a dealbreaker for you. For some people, dating someone also means dating their family, and being hurt, insulted, or alienated by their partner’s family would make the relationship untenable. Other people find that external influences like other people’s opinions and behaviors are much less of a factor when determining whether a relationship is going to work. Both perspectives are totally fine; they just differ across people.

My first suggestion would be to talk to your partners whose family members are saying these hurtful things. Maybe what you need is for them to stand up to their family: “You may not approve of my relationship with Xaniel, but you need to keep that to yourself. Speaking unkindly or disrespectfully about my partner is not okay and I will not tolerate it.”

Maybe the answer is to spend less time around these family members and stay in social and relational spaces that are safe for you. That is totally okay too! You have the right to set boundaries that are healthy for you: “I know you wanted to do Thanksgiving with your family, but last time I visited, I ended up in a lot of pain and doubt after how they talked to me and about me, so I’m going to be elsewhere this year.” 

I don’t think this is necessarily a sign that polyamory isn’t for you - perhaps this relationship isn’t for you, if the emotional minefield surrounding it is something you can’t or don’t want to navigate. Perhaps simply the current arrangement, where you’re around for these family members to say nasty things, is what’s not working. In general, if something is making you happy and working for you, and other people are being mean about it, the solution is not to stop doing the thing - it’s to either stand up to, or ignore and avoid, the people being unkind.