Holding on is always in regard to attachment to some need rather than to love . It is itself a compensation for lost bonding .
To let go is to end depression and begin a new flow.When you let go, something always better comes to take the place of what you let go of. LETTING GO allows new bonding to take place and increases your self-love and attractiveness .The more you hold on, the more your sense of self-worth goes down because you made your self-worth dependent on something outside you using it to meet some need.
LETTING GO restores your power back to you.