You are allowed to define your own boundaries. Love bombers tries to put you on guilt trips.Don't worry, you aren't setting any unrealistic boundaries.
Listen to your gut feeling
Be mindful of what you feel. There is a reason why you are feeling insecure in your relationship.Maintain a journal and track down your emotions to identify the reasons.
Talk to someone you trust
It's difficult to manage the emotional manipulation all by yourself. Vent out your thoughts to someone you trust and is experienced or mature enough to understand you.
Tell your partner you want to take things slowly
Your needs are just as important as theirs, so it's important for you to communicate it to them that they should respect your pace.
Learn about the difference between healthy and unhealthy relationship
Review the characteristics of healthy relationship and compare it to what you are currently going through.