The Island Boys had trouble brewing long before Franky Venegas ended up in the slammer over the weekend on gun and drug charges … cause TMZ’s learned the twins officially called it quits a while ago.

Alex, AKA FlyySoulja — Franky’s twin brother and the other half of the Island Boys — tells TMZ … the duo has been officially dunzo for a long time after not seeing eye to eye for some time. In fact, Franky officially packed his bags and dipped out of their shared Florida home over a year ago.

Flyy tells us he and his brother were constantly butting heads and having intense arguments. Flyy says his path is drastically different from his brother’s, and he doesn’t vibe with Franky’s lifestyle as of now.

Flyy recently got engaged on Valentine’s Day to his baby mama, who he shares a young son with. He has a 4-year-old daughter from a previous relationship … and he considers himself a family man these days.

Despite the brothers not currently seeing eye to eye, Flyy tells us he’ll always have his brother’s back. In the past he’s helped him cover lawyer fees … but claims Franky’s always thrown it back in his face, telling him, “You’ve done nothing for me.”

Flyy says he feels they both have growing up to do … and hopes they can find their way back to each other some day. But as of now, they’re barely seeing or speaking to each other.

So much so, since Franky’s arrest in Naples over the weekend, Franky’s been trying to reach his brother … but he keeps missing his calls.

Franky was arrested and charged Sunday with possession of a controlled substance without a prescription, and possessing a firearm with an altered serial number.