Pretty much any two lines can come after this, as long as the last word of the last line rhymes with "Blue." A few examples are...
Roses are red and violets are blue, Got kids in my basement and I'm coming for you!
Roses are red and violets are blue, Your mom is gay and so are you!
and the most common...
Roses are red and violets are blue, sugar is sweet and so are you!
Someone who jumps from one relationship immediately into another one.
Serial monogamists can not stand to be alone and often suffer from vast commitment and insecurity issues.
Because they jump into relationships immediately after the previous one has ended, serial monogamists typically don't take the time to reflect on their behavior or why their previous relationships failed; thus, they end up making the same relationship mistakes over and over again.
Person 1: Damn, Dustin already has a new girlfriend?! It's only been two weeks since he broke up with his fiance! I think he's a sociopath.