Rapper YC -- Ex-Fiancee Willing to Take His Creeping Ass Back

Rapper YC has been granted a stay of execution -- the ex-fiancee he cheated on the night before they were supposed to get married ... is willing to give him a second chance with one BIG condition.

YC's lady, Tia Anderson tells TMZ ... the wedding could be back on IF he can stop creeping behind her back -- particularly when he's about to walk down the aisle! We broke the story -- Tia called off their Las Vegas ceremony last month when she caught him messing with a bartender.

Tia says she and YC haven't seen each other since things blew up less than 3 weeks ago, but they are texting and talking -- and he even sent her roses. He's gonna have to do way more than that.

She says the biggest issue is YC laying off the rapper lifestyle -- meaning, stop surrounding himself with groupies and THOTs. YC claims he's down to do what's necessary -- including couples counseling -- but Tia's still deciding whether she can trust him again.

Translation: His punk ass needs to suffer for a while.

Tip for YC: Record something romantic, instead of songs like "Racks." Also ... stop hooking up with random chicks.