Community Note - Credit for this Subclass has to go to PointyHat user. I know he created this, I couldn't find it on DNDBeyond and a Player wanted to use it for a homebrew campaign I'm running. This is my take on it, only thing I've adjusted is the Level 7 Beloved concept, offering a higher risk Tier for Beloved vs. the base Paramour.

The Oath of Love is a subclass meant for those who wish to play a paladin not necessarily tied to any notions of alignment. The very concept of the subclass goes against the traditional idea of the paladin as the unfeeling, holier-than-thou warrior for good, giving it a very “human” and emotionally raw motivation. The subclass also aims to spark roleplay ideas by offering the concept of the beloved, the source of the paladin’s love, which the player can use to inform who their character is -- how and why did they fall in love with their beloved? -- and which the GM can also use to create situations that call back, reinforce, or put the paladin’s beloved in danger, to name a few.

Gameplay-wise, the subclass has been designed for a role the paladin has not had a chance to fully embody yet: buffing. The Oath of Love is designed as a buffing tank, meant to stay in the field and absorb hits while empowering their allies to dominate their enemies, keeping up with them through both smites and their own bonuses that depend on positioning. All of their spells but the first are either buffing or tanking spells that are not in the paladin’s spell list, giving you added versatility to your spellcasting, and both of their Channel Divinity options allow you to help your allies, but this subclass’ signature ability is the mechanical aspect of choosing your beloved in the battlefield. A willing creature that you choose as your beloved gains a number of very powerful bonuses, provided they stay within your aura, and in turn you also gain bonuses by fighting alongside them. This further exemplifies the theme of love and the role of the paladin of love as a warrior that cherishes and protects those they love.

Channel Divinity

 

• Loving Embrace. You can use your Channel Divinity to uncloud the feelings of a loved one, returning their mind and body to their control. As an action, you touch a creature. The creature is immediately free of the following conditions: charmed,frightened,incapacitated,paralyzed,petrified, andstunned. The creature is also free of any other effects that negate their free will, such as possession.
• Galvanizing Affection. You can use your Channel Divinity to channel the strength of your love into an inspiring, rousing cry that empowers your loved ones. As an action, you present your holy symbol and choose a number of willing creatures (that can include you) equal to your charisma modifier. For 1 minute, these creatures add half of your charisma modifier, rounded up, to their damage rolls.

Aura of Love

Starting at 7th level, you can empower your allies, and especially your beloved, with your love. When a friendly and willing creature within 10 feet of you makes an attack roll, you can use your reaction to add your charisma modifier to their attack roll.

Additionally, you can use your bonus action to select a friendly and willing creature within your aura. This creature is now your Paramour, and enjoys a number of bonuses while in your aura:

• They add your charisma modifier to one of their attack rolls per round.
• Their AC increases by 1.
• They are instantly stabilized if they drop to 0 hit points.

The creature counts as your Paramour for 1 minute or until they leave the radius of your aura. At 18th level, the range of this aura increases to 30 feet.

Alternatively, you can use your bonus action to choose a friendly and willing creature in your Aura as your Beloved. True love involves sacrifice and vulnerability. As their Beloved, this creature will be buffed by the power of the Paladin's love, while giving the Paladin additional vulnerability as a result.

• The Beloved adds your charisma modifier to one of their attack rolls per round.
• The Beloved's AC increases by 2. The Paladin's AC decreases by 2.
• The Beloved and the Paladin are instantly stabilized if either drops to 0 hit points.
• The Beloved rolls attacks with Advantage. Attacks against the Paladin are rolled with Advantage.
• Once per Round, either the Beloved or the Paladin can use a Reaction to transfer up to 15 HP to the other. 

 

Empowered by Love

Starting at 15th level, you become stronger when fighting side by side with those you love. When the friendly and willing creature you have selected within your aura as your beloved/paramour is within 10 feet of you, you enjoy the following bonuses:

• You add a +1 to all your attacks and damage rolls.
• Your AC increases by 1.

 

These effects net out with Aura of Love/Chosen Paramour/Beloved buffs & nerfs.

Knight of Hearts

At 20th level, you become the living embodiment of the love you feel so strongly, which gives you and those you love the following benefits:

• You can choose a number of friendly and willing creatures equal to your charisma modifier as your beloved. They all enjoy the same bonuses while in your aura.
• You add a +2 instead of a +1 to all your attack rolls, damage rolls, and AC as long as there is a conscious beloved within your aura.
• When fighting with a Beloved, attack rolls against the Paladin are no longer rolled at Disadvantage.