A harem.
Harem is a relationship where one can have two or more love interests at the same time with all of them knowing about each other and living happily.
Alice and Ann knew about it, and they were ready for it.
They were the ones who wanted to make it in the first place.
'We don't deserve to have Alex all for ourselves, it would be too much for us.'
This is what they thought.
It was not like they didn't want to be loved by him alone.
They would be lying if they said that they didn't want to be the only one Alex loves.
They knew that if they were Alex's only lover, the love that Alex could give them, the care that Alex could give them, and the protection that Alex could give them would be too much for them alone.
A relationship is about balance, we love someone, and they love you back.
If one loves the other a bit too much, and the other can't do the same, the relationship turns bad in one way or another.