There’s a part of me that will always believe that Angel is Buffy’s true love. That there will be a piece of her heart that will always be with him for the rest of her life. It doesn’t mean that’s the person that she’s meant to be with eternally.
The thing about Buffy and Spike is they understand each other on a level that nobody else understands her. They’ve both lived a hundred lives and I think there’s a connection there that we will see evolve over the next couple of years where she realizes that he really is someone that she can trust, someone that’s a companion to her and someone that really understands her unlike anybody else.