LW1's partner is entirely reasonable in his demands for sleep, and she is being very childish if she gets weepy because life isn't like films.

Most people twitch in their sleep, which is enough to wake anyone entwined in their arms. Other things which cause bad sleep are body temperature too high, snoring and lack of movement. All these things have to be overcome if people are to sleep sucessfully entwined, but any one of them is enough to deny sleep to one or other partner.

In my (admittedly limited) experience, sleeping in someone's arms for longer than about ten minutes only happens in films, never in real life. If LW1 is used to doing this, it may be that lack of sleep of her partner induced her previous break-ups. Sleep is a fundamental human right and she cannot deny it to her partner. If she needs to cuddle something, buy a teddy bear.