1. Have an open and honest communication. Provide them with a safe space to express their insecurities without judgements. This will help them deal with it in a healthy way. 

2. Discuss boundaries so that the expectations of both partners are met. Make sure to have this discussion multiple times. Sometimes couples therapy can help to negotiate and safely discuss these issues in a relationship. 

3. Listen actively and empathetically. This will make them feel heard and valued. It will show that you truly care for them. 

4. Provide verbal and physical affirmation and reassurance of your love and commitment from time to time. 

5. Boost their self-esteem. Help your partner build their self-esteem through positive reinforcement.

6. Avoid actions or behaviours that can trigger insecurities and work together to minimise them. Work towards building their trust in you. Consistency, reliability, and transparency in your actions can help rebuild trust. 

7. Encourage personal growth and self-improvement to boost their self-confidence. Help your partner with stress management techniques that can aid in coping with their emotions and build resilience.

Remember that addressing insecurities takes time and effort from both partners. A healthy relationship is built on understanding and nurturing each other's well-being.