Formal/Literary:
* Custos meus: Literally "my guardian," this could be used for a protector or someone who watches over you.
* Conservator meus: "My preserver," suggesting someone who maintains or protects something.
* Curator meus: "My curator," implying someone who takes care of something valuable, like a collection or a legacy.
Informal/Affectionate:
* Custos meus carus: "My dear keeper" - adds a touch of affection.
* Protector meus: "My protector," implying a strong and reliable guardian.
* Amica mea custodens: "My friend who keeps me" - emphasizes a close, supportive relationship.
More specific meanings:
* Domina mea: "My mistress," could be used if the keeper is a woman who has power or authority.
* Dominus meus: "My master," could be used if the keeper is a man who has power or authority.
Ultimately, the best Latin phrase will depend on the specific relationship you want to convey.