Accept
First of all I want to make it clear that you don't have the right to chose who your boyfriend is friends with. Maybe she is a b.... in general, but apparently their relationship is rewarding towards David, because why else would he still care for their friendship?
You got to ask yourself what it really is that you want from David. Apparently there's a squabble between you and Donna, and even though you haven't got any part in it, one can't force anyone to like you. But David shouldn't have to meddle or chose a side, and asking him to stand up for you is really asking him to take on YOUR issue and meddle in something that's not his business. Perhaps even give up his friendship.
I understand that you feel like David is there for you and I understand that it's very painful.
But right now the table is actually turned. David needs YOU to be there for HIM. He needs you to love him enough to feel happy in his behalf that he got a friend he can trust. And he needs you to be so large as to accept that we can't be loved by all and as long as his friendship with Donna is rewarding you will turn your blind eye and ignore her totally childish behaviour.
Not because of her - but because you love David and want what's best for him.
Don't think about that you want from your boyfriend - think of what you can give him instead.
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