You're mixing up several different things here.
A 'place to stay' and 'own bedrooms' are not the same thing. As I and several other posters have stated. The children can still stay over in a 2 bed-flat. I mean, if the OP feels that strongly about bedrooms she can sleep on the sofa when they visit, and they can have the rooms.
I didn't say it was unfair for OP to be upset, she can feel whatever she likes but the ownership of the family home is a fact. Even if she had no issues with rent the LL could sell up - and then what?
@Jellycatspyjamas I wasn't implying that OP should have known. But she has said a few times she has done 'everything' right. That's simply not true. Not the OP's fault, but she hasn't had a smooth sailing life and suddenly found herself in this position.
@wombat15 You keep accusing people of being nasty and having a go. But we're just pointing out the fact. It's not about what OP has or has not done. It's where she is now. And she is in a good position despite everything that has happened. She doesn't feel that way, because everyone else around her seems so much better off. but she is!
Other posters have weighed in to point out that they never even had a 3 bed, or are having to downsize etc. The whole point of this AIBU is whether OP is being U, and people have shared their own experiences. If OP doesn't like what she's hearing, fine, but they're the facts, the rest of us can't d anything about it. Her friends are not the norm, they are privileged to be able to provide rent free homes, support for their kids to study, etc. OP has raised two high achieving children who are off to uni. She should feel proud, not guilty that she can't offer them more to the extent of a bad impact on her mental health. What good is her being angry, comparing, or us sympathising going to do?