I went ahead and took 10 English idioms about love from here, then picked their equivalents in Russian.
Look what I've got:

A match made in heaven – two people who are extremely compatible and will have a great life together
- Мы (вы, они...) созданы друг для друга
- Сами небеса послали мне тебя

To fall head over heels in love – to fall completely in love
- Я в тебя влюбился без ума
- Я в тебя безумно влюблён
- Я тону в твоей любви (lit:I'm sinking in your love)

To be smitten with someone – to be completely captivated by someone and feel immense joy
- Я сражён наповал (fig: as if shot/stabbed dead by you)
(Впервые увидев её, поручик был сражён наповал.)

To be the apple of someone’s eye – to be loved and treasured by someone, normally a parent
- Ты - свет в моём окне (also poet. свет души моей)

To be a soul mate – to be someone who understands and accepts the other person completely
- Мы с тобой - родственные души.

To take one’s breath away – when you are so in love with that person that you find it difficult to breathe
- Когда я тебя вижу, у меня аж дыхание захватывает, какая ты красивая. Не могу налюбоваться.

To be someone’s one and only – to be unique to the other person
- Ты - моя единственная любовь навеки!

To have a crush on someone – an informal idiomatic expression that describes young romantic infatuation
- Она в него влюблена по уши с тех пор, как они учились в университете.

To fancy someone (British English) – to find someone very attractive
It's actually not an idiom, just a verb. The Russian look-alike is: засматриваться на кого-то...

To love someone with all of one’s heart and soul – to love someone completely
Люблю тебя всем сердцем (всей душой). Looks like a direct translation, but these two are common bookish cliche here.

Also, there are things like "безбрежный океан моей/твоей/его/её любви", "тонуть в чьей-то любви", "купаться в (лучах) чьей-то любви" etc, but they don't seem fixed expressions whatsoever. They're just occasional stuff that you can think up on your own without any limitations.

Is that what you wanted?