Yes, attachment feels good. Very good, in fact. But, that's the reason, it brings the bad, the jealousy, the control with it.
We can truly love without attachment. Attachment is nothing else but a thought unwanted. Because when you are with the person, it is quite hard to muster up the bad part of attachment. You are too much into them at that point of time.
Then, you are away and you think what they would be doing. Thus, starts the roller coaster to hell, step by step, not instantly.
To not attach would mean to only have thought of that person when you are with them whether physically or virtually.
To not attach would mean you will be 100% with them, when you are with them. That would be truly loving somebody.
Yes, attachment prevents us from truly loving somebody because no matter what when you attach, you bring negativity. If not anything, you will start fearing losing them. There is no way out of it except to not attach.