Originally Posted by thunkybunny
Sadly, that isn't so reliable when that partner manipulates the situation out of jealousy given their partner's NRE. Kinda lame really. I guess it means that the established relationship is too weak for new partners to enter.
I agree. And, if that is a possibility, that in itself is a huge red flag.
I would add, from my experiences:
1. When boundaries are being renegotiated over and over again in a short amount of time.
2. When boundaries that are already negotiated continue to be questioned or subtly violated by one party or another.
3. When the new relationship is moving too fast for the established partner (ie conversations about how x would like y to move in after their kids are grown when they've only been dating for a couple of months)
4. When one pair in the relationship starts making huge life decisions without the other(s) and then informing those others of these decisions later
5. When there is repeated miscommunication and misunderstanding despite loads of communicating
6. When things that were 'deal breakers' in the original relationship (such as no kids, no selling the house, no pets, etc) are overlooked in the new partner
7. When the new partner is given opportunity to ask questions and says that they 'have none'
8. When the new partner suggests (even once, and especially repeatedly) that something is wrong with the existing relationship (such as abuse, codependency, inequitous income)
9. When scheduling becomes a stressful activity for even one partner
10. When negotiations do not result in compromises but merely one party convincing the other to let them do xyz
11. When one party changes their mind about something (a boundary, an event, a schedule, etc) and the other(s) refuse to consider that change; put another way, when one party or more seems to make lots of snap decisions rather than allowing adequate time for careful consideration
That's all I can think for now but I am sure more will come up.