Fidelity to me is more the emotional bond. If you love someone, you don't want that energy to spread on others, so fidelity is like a key, that keeps you open to that person, and closed romantically to others. Loyalty is to me more cognitive bond that gives you strength to give constant support and mental stimulation to that person in a special way that no one else can provide to that person.
To me they are similar. I want it all.
Love and loyal
Fidelity and trust
Fidelity and loyalty
Fidelity and love