Here's what we can gather:
* They are rivals: Their primary dynamic is one of fierce rivalry, often leading to direct confrontations. Shadow sees Metal Sonic as a flawed imitation of himself, while Metal Sonic is programmed to be the ultimate Sonic, thus viewing Shadow as a threat.
* Metal Sonic's programming: Metal Sonic's actions are driven by his programming, which emphasizes defeating Sonic and achieving ultimate power. This means that any "love" he might feel for Shadow is likely not a genuine emotion but a twisted interpretation of his programming.
* Shadow's personality: Shadow is a lone wolf, often reluctant to form close bonds. He values strength and independence, making it unlikely he would develop romantic feelings for anyone, including Metal Sonic.
Fan interpretations:
Some fans interpret the rivalry between Shadow and Metal Sonic as a more complex relationship, possibly even bordering on a love-hate dynamic. However, this is largely based on speculation and creative interpretations of their interactions.
Conclusion:
There is no official confirmation or indication that Shadow and Metal Sonic are romantically involved. Their relationship is primarily one of rivalry and antagonism, driven by their contrasting personalities and goals. While fan interpretations can be creative, it's important to remember that the canon doesn't explicitly support any romantic connection between them.