Do not let your past control your today and the future. That is a one way to overcome insecurity and jealousy in a relationship.
Insecurity in a relationship is caused by two mental factors: negative past experiences and the fear of the unknown. While Jealousy is usually caused by lack of transparency, trust and a feeling of revenge.
Climb on the big stone to get rid of bad feelings in your relationship -- trust. Show me a trusting couple and I'll tell you the meaning of happiness.
Urge your partner to be open to you by talking heart to heart, at least once in a while. Do not do it frequently, it freaks out. Influence your partner to be sharing in terms of problem faced outside the relationship by doing the same. It gives both of you an assurance of trust, which do away with the insecurities.
An opposite of the negative vibe - jealousy, is true commitment. A genuine relationship supports and always gives a clear picture of oneness.
Realize that jealousing your partner can also cost you alot. If you cannot benefit when your lover gets a promotion, then you're not in love. If you're not happy when your partner is complimented, then you need to apply self-awareness to overcome.
Another way to overcome insecurity and jealousy in both of you is to consider the power of teaming. Solve your problems together. Learn things together. Develop the 'WE' instinct rather than the 'I' old intuition.
You don't need to be more than your partner. What matters is contentment. Be happy with yourself in any circumstance and pursue your goal with hope.
If you're alone struggling with insecurity and jealousy, do not tell your partner. Just do the above measures to re-kindle love, affection and togetherness among yourselves.