Ashton and Mila, who starred alongside each other in That 70s Show, were snapped kissing this week but are yet to confirm a romance.

Demi was reportedly "devastated" when she saw the pictures and is "beyond heartbroken" an unnamed source told RadarOnline.

"Even though Ashton cheated on her all the time, it was with random girls, it wasn’t a relationship like it is with Mila and that is what is killing Demi now," the source said.

"Seeing photos of him kissing another woman is too much for her to handle, it's like having her nose rubbed in it time and time again. She kind of knew it was definitely over between them but I think she was still holding out a little hope for reconciliation — now he's actually dating someone else she knows that's not going to happen."

Demi, who has spent time in rehab since the pair's split in October, 2011 was already finding it difficult to cope with the break-down of her six year marriage. Friends of the troubled actress now fear that she will find it even harder to cope.

"Each time Demi hears about Ashton and Mila it breaks her heart. She really loved him despite the flaws in their marriage and to see him dating someone new, who is so much younger than she is, is like a knife in her heart," the source said.

Even Demi's daughters Rumer, Scout and Tallulah have distanced themselves from their mother in an act of tough love and have been considering a restraining order against her.

Her daughters supported her through her break-up with Ashton and rehab, but now they don't want to "deal with the drama" surrounding their mother and feel that they need time out.