Between lillends, succubi, and erinyes, love and lust have almost every aspect in D&D represented... except one very important one. Where are the defenders of marriage as the reliable, comforting rock of an orderly, strong community? Doesn't Mt. Celestia send a local to the cheesecake competition? ;^)
I joke, but it's a good niche (and some artwork of the beings described below could be cool). Presented below is the one I just wrote up today. It's described in Pathfinder format, but it's fairly easy to convert to the old 3.5 version: replace Acrobatics with Jump, K(religion) with Tumble, and Perception with Spot, mostly. "Heaven" becomes "Arcadia, Mt. Celestia, Bytopia, and Elysium." References to Erastil are replaced with your preferred LG gods with a portfolio involving family or community (for which there's rather a lack in core... Yondalla and/or Rao, maybe).
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We consider love a good thing, an important thing, and every culture has an enormous number of rules and traditions surrounding it. A community with strong morals regarding sex and marriage, a rich tradition of courting and romance and abiding family ties, is a community resilient in the face of enormous shocks. It's one that will be happy and healthy. And that's exactly the kind of community Erastil likes. So here's an angel that stands up for the sacrament of matrimony, for lifelong love, by giving us an eternal example of fidelity rich with love, sex, friendship, and family. In fact, it's such an important job, here's two.
FIDELES
A fidele usually appears to be a towering human, though other races are not unknown, with the antlers of a deer, elk, antelope, or similar creature, and deep, dark eyes. Male or female, they are gentle in mien and physically impressive, usually quite attractive: strong, healthy, vibrant with the life of the natural world. They are almost always encountered in married pairs promoted from petitioners among Erastil's faithful. This origin means some fideles have attributes rearranged from those presented here; for example, in a pair one often carries a pair of light weapons for melee combat while the other carries Erastil's signature longbow and switches the Str and Dex attributes.
Erastil charges fideles with exhorting mortals to respect the bonds of marriage and enjoy it to the fullest when it is achieved. Their feelings for their spouse are deep, joyful, and often on unabashed display. They assist licit lovers that face obstacles and punish adulterers, rapists and other offenders against love. Shelyn is also known to call upon them for these missions, while they are often demurely aghast at the behavior of Calistria and her faithful.
Fideles often advance as rangers, taking as a favored enemy either outsiders (evil) or mortals similar to the humanoid form they bear, the companion-bond version of hunter's bond, and the combat style that favors feats they already have. A few become clerics of Erastil.
Fideles (singular, Fidele) CR 7
LG Large Outsiders (Angel, Extraplanar, Good, Lawful)
Initiative: +3; Senses Darkvision 60 ft, Listen +13, Spot +13
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AC 17, touch 12, flat-footed 14 (–1 size, +3 Dex, +5 natural)
HP 45 (7d8+14)
Fort +7 (+11 versus poison), Ref +8, Will +8
DR 10/evil; immune electricity, petrification; Resist fire 10; SR 18
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Speed: 40 ft.
Melee Short sword +11 (1d8+5/19–20) or
Ranged Composite Longbow +9 (2d6+5/x3)
Full Attack: Melee Short sword +9/+4 (1d8+5/19–20) and short sword +9/+4 (1d8+2/19–20) or
Ranged Composite Longbow +9/+7 (2d6+5/x3)
Special Attacks: Charge +11 (1d8+7)
Spell-Like Abilities (CL 3rd):
At-will: Guidance, Light, Purify Food and Drink, Stabilize
1/day: Bless, Detect Evil, Protection from Evil, Consecrate, Cure Moderate Wounds
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Abilities: Str 20, Dex 17, Con 15, Int 14, Wis 16, Cha 18
Base Atk +7, Grp +11
Feats: Run, (Two-Weapon Fighting and Improved Two-Weapon Fighting) or (Point Blank Shot and Rapid Shot)
Skills: Acrobatics +15, Climb +15, Craft (any one) +14 or Profession (any one) +13, Diplomacy +16, Heal +13, Knowledge (nature) +12, Knowledge (religion) +12, Perception +13, Sense Motive +13, Survival +17
Languages: Abyssal, Celestial, Common, Infernal
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Environment: Heaven
Organization: Mated pair
Treasure: Standard
Advancement: By character class; Favored Class (ranger)
Level Adjustment: +6
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Special Abilities:
A fidele’s natural weapons, as well as any weapons it wields, are treated as lawful-aligned and good-aligned for the purpose of overcoming damage reduction.
Ever Touching (Su): All fideles wear wedding bands, some ornate and some simple, that are part of them and connect them to their spouse. In many ways, they are one being. They are constantly aware of their mate's state as per the status spell. The pair share a single pool of totaled hit points which is affected by any wounds or cures either receives; when this pool is 0, both fideles are disabled, and the boundary between dying and dead is set by the lower of the two Constitutions. Any other baneful effect that would lower the hit points of a fidele, such as negative levels, Constitution damage, or other effect must first overcome any relevant spell resistance, magical defenses, or saves from both fideles, but if it does so it affects both fideles equally and fully. For example, both fideles must fail a save versus poison, but if they do, the poison affects both; if an enervation spell is failed by both fideles, it affects both with the same number of lost levels, and the total number of hit dice lost is subtracted from the common pool. Vice versa, if one fidele makes a stabilization check or a continuing save against poison or disease, both are safe.
The GM should adjudicate any unusual effects with an eye toward maintaining the shared status of the fideles. If their wedding bands are removed, by theft or violence, the more precise status effect is suspended but the shared life is not. The bands are useless to others: a fidele will never remove theirs willingly, and when a pair of fideles is slain, the bands cease to function; the rings are useful only as particularly foul trophies. It might be theoretically possible to kill one fidele and not the other, but the task would be extremely tricky. It is just the sort of twisted experiment fiends enjoy trying, but to date, no such project is known to have met with success. Since a fidele without a spouse is not a fidele, speculation is either that they would return to petitioner status (and desperately seek powerful magic to restore their spouse to eternal life) or fall and become some flavor of fiend, likely an erinyes.
To my Lover's Side (Sp): If separated from its mate, a fidele can use plane shift and greater teleport both once per day to the plane and immediate physical vicinity of their mate.
Unshakeable Fidelity (Su): No mind-affecting effect whatsoever can cause a fidele to act against the interests of its mate as it would rationally understand them.
Alternate Form (Su): At will, a fidele may change between its humanoid form and the form of a deer, elk, or antelope -- whatever species of animal its horns specify.* They may also change into medium specimens of whatever humanoid species they appear as.
(*Wondering why? These are some of the only monogamous mammals.)
Tongues (Su): Fideles can speak with any creature that has a language, as though using a tongues spell (caster level 18th). This ability is always active.
Memory (Ex): Unusually for ex-petitioners, fideles fully remember their time as mortals unless later effects damage their memories. Erastil is a very old god; some fideles have memories of ancient histories indeed.
Skills: Fideles have a +4 bonus on Survival checks.
It seems balanced, and I love the flavor, although I think it would be better if they were not tied to a god.