Свой behaves like мой, твой, ваш and наш. It acts as an adjectival modifier: муж is masculine and is in Accusative. The modifier follows.
The question remains unanswered. According to http://www.russianlessons.net/grammar/pronouns.php, at "Reflexive possessive pronoun 'Свой,'" the table shows masculine Accusative Case (animate) as Свой or Своего.
The choice of the form depends on the animacy of the noun. Муж is an animate noun, so its Accusative reuses the Genitive form. Свой just follows.
- it is consonant-ending masculine nouns that exhibit this behaviour. In the plural the rule applies to all nouns.
And is свойl used with Ты as well: "Ты любишь своего мужа"? Or would I have to use Твоего?
Свой is "oneself's" for whatever the grammatical subject is (it also supports some functional subjects).
Your question is how свой differs from мой (these are nominative). Свой is "one's" and Мой is "my." We don't use "one's" in (American) English much because... well... one doesn't talk like that. One's vocabulary doesn't utilize it a lot. (Works like that.)
You also asked whether своего or моего (the Accusative or Genitive forms) could be used. Keep in mind the Tips & Notes from the "Family" section:
Unlike English, Russians rarely say "my mother", "my grandfather"; usually they omit "my".
...And when they don't, it is more natural to use reflexive "свой" (one's own).
In response to another user on this same thread, своего is not "us."
(Edited because for some reason, something I did with formatting gutted a couple of paragraphs.)
How would it be "i love her husband" or "i love your husband"? Can i use "своего" in these cases, or it need to be related to the person in the sentence (in this case me) for using it in this form making it mandatory to use "ваш" for example just for making it clear?
Those sentences would use «её мужа» and «твоего/вашего мужа» respectively. Свой refers to the subject of the clause.
No matter what i do it still makes me feel like the person who is loved belongs to somebody else :)
It refers to the subject of the sentence (or the clause it is in).
Here, "I" is the subject, so the English translation uses "my" (English does not have a possessive that means "oneself's")
oh ok. So when I is the subject it means my, when she is the subject it means her and when he is the subject it means his?
When I is the subject it means my (own), when she is the subject it means her (own), and when he is the subject it means his (own).
Not absolutely wrong (and it's an accepted answer) but своего is certainly more natural. If the subject was она, it would be wrong to use её instead of своего as that would imply that she loves another woman's husband.
If I were to replace husband with wife, would I use "своеё" or something else?