Depends on what someone can mean by "exist".
On the one hand, you have a metaphysical feeling that is the result of neurochemistry (like all emotions) that we call "love". We can show existence for it by looking at the brain's chemistry and finding what chemicals are used to create these feelings. So, while "love" doesn't really "exist", we do have the chemicals that result in a reaction in our brain that is describable as that feeling. This does make it hard to achieve any real sense of a conscious deity that some how doesn't exist on the physical level, but can invoke feelings on the emotional, reactional level that isn't a part of that things brain. This makes it even harder to argue for when you argue for the next part, down there as well.
On the other hand, you have people trying to argue for some kind of physical reality or something that can affect reality. These are arguments that try to argue that a non-existent, non-physical item can somehow affect the physical in some way, despite no real explanation given. These are more or less nonsense since you would need to violate physics in order to accomplish this on some level without fucking the whole system up in the process (and only God knows how that would work). And of course, you could just get even more and more meta about it if you wanted to. Philosophical arguments tend not to have any actual bearing on reality after all.
TL;DR: It is hard to argue for the existence of a meta-physical without a physical construct to initiate feelings of said meta-physical.