We don't recommend going from monogamy to polyamory without having done a lot of work in therapy, and deconstructing societal scripts around relationships, expectations, consent and boundaries.
That is respecting more boundaries, not just sex, and understanding what is and isn't a boundary.
Beings trying to put 'boundaries' on what they are allowed to do with other beings for example isn't actually a boundary it's just an attempt to control other's behaviour because they're afraid of losing them instead of trusting them or realising that beings should be allowed to make their own choices, even if it means against you.
This may sound doomery in that like they will choose to no longer be with you, but in our experience that is usually caused by holding on too tightly instead of letting beings be free.
We have been on both ends of the 'too tightly' side and it was never nice.