Sounds like you're afraid of losing the attention -- that might be where the jealousy is coming from.
If you're not sure you really want a relationship... then it's probably a good idea to not get in a relationship until you're more certain.
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen