Hey there. I am sorry you are in such a complicated situation. I hope we are able to help.

I agree with your opinion that Sam and Alex's relationship is a toxic one, especially on the part of Sam. The behavior they are exhibiting is quite concerning, to be honest. They seem to be trying to control their partner and that can lead to abusive behavior. I don't feel it's safe for them to be together, and I don't really think it is safe for you to be in the middle, either.

All we can do in life is make our own choices, to the best of our ability, given the resources we have at that time. We can't let other people try and control our lives; it just doesn't work. Sam is out of line, and honestly I think it's safer if you and Alex are away from them. I wouldn't get in the middle of this if you can help it, because Sam's actions are stemming from their own insecurities, and they need to have an open, honest talk with Alex about what is really going on with them. But I will say this: if Sam gives you an ultimatum, I advise you pick Alex. Ultimatums are inherent unhealthy and generally relationships don't repair themselves well after one is given. Sam is in the wrong here, and if you are forced to choose a friend in this situation, I would choose the supportive one who is not exhibiting abusive behavior.

That's just my two cents, but I hope it helps you. Again, I am sorry you are in this situation. It really sucks, but I hope you choose to take care of yourself as best you can, because ultimately you gotta look out for number one: you.