Hullo and welcome!
The biggest obstacle you will have to face is to figure out what you want, and who is compatible with you. And to accept that not everyone who falls your way, sadly not even everyone whom you develop a liking to, is going to want the same things. And that you might find unexpected things along the way - a man, a lesbian woman, a woman who is only interested in a relationship with you, a woman who is only interested in a relationship with your husband - and to be open enough to embrace that when appropriate.
In triads, people want different things at different paces. Like RP said, it's crucial to give it time and not to push your own agenda. Develop an awareness of how you communicate and deal with issues like stress, ambivalence and conflict, and educate your partner(s), too. Especially if somebody in your configuration is more likely to avoid open conflict and needs a lot of support in voicing their opinions and concerns, have built-in "safety" mechanisms to ensure that the more determined partner(s) don't just enforce their own comfort levels and goals on others. Written communication works great in some situations because it gives time for formulating and processing of thoughts.
And most importantly; don't let conflicts and insecurities fester! Don't wait that your partner(s) notice something is wrong and bring it up for you.
Me: bi female in my twenties