The "Sure Thing" singer's high school sweetheart, Nazanin Mandi, beelined it to court Tuesday and filed to divorce Miguel after nearly 3 years of marriage.

According to the documents, obtained by TMZ, Miguel's wife is citing irreconcilable differences as the reason for the split and she says there is a prenup.

Miguel and Nazanin reportedly announced in September 2021 they were separating after 17 years together ... but he seemed to hint they were back together in February, when he posted a photo dump of them on Instagram with the caption, "Love heals. Proud of us."

The couple was photographed together as recently as July and in the docs, Nazanin does not list a date of separation ... that section of the paperwork says "TBD."

Miguel met Nazanin when he was 18 and they got engaged in 2016, before tying the knot in November 2018. They did not have any children together.