Shakespeare's "love triangle" sonnets: any other such poetry exist?

[mike thomas]

Hi all, apologies if this subject is in the wrong forum, badly phrased, or maybe too deep:

Many writers claim that Shakespeare's Sonnets involve a love triangle: I have been looking for an example (other than Shakespeare's) of sonnets which use a love triangle as its basis, without any luck: Perhaps Shakespeare's work unique in this respect:

Can anyone please help with this?

Best regards and thanks for taking the time:

[YesNo]

When you mean a love triangle are you including poems about infidelity? I suspect there may be many of those. For example, Sharon Olds, "Stag's Leap".

[mike thomas]

Wow that was quick! Thank you YesNo:

I mean a poem/sonnet ( or anything whatever) in which the writer/author addresses two other individuals as lover, but those individuals themselves love each other:

As for the era, I was hoping for anything before 1609 - the year in which Shakespeare's sonnets were first published: I have tried all the usual suspects: Jonson, Marlowe, Sydney etc. but as yet without any luck: I am aiming to establish who set the precedent:

Thanks for the input:

[mike thomas]

It seems then that WS sonnets are unique in this respect