Unwanted Mating Bond

Two complete strangers, The most Next in line to be Alpha of Green hell pack and The next in line female Alpha of The bloody pack were trapped into Arranged mating to emerge their packs.
 
They weren't supposed to be mated to each other, but their younger siblings. But somehow they found themselves with no choice but to be mated to not look like fools.
 
 
 
Life was good, except that Julia's ex-boyfriend Alpha Mark couldn't let her go. So, he kept doing his best to ruin that mating bond. He even kidnapped her.
 
 
 
With possessive Alpha like Alpha Xander, Julia had no choice but to submit to her mate. They  were so forced at the beginning, but later she realized that he was her real mate.
 
Love bloomed, but soon dimmed when her mate Alpha Xander disappeared after leaving her the cruel, harsh letter, breaking the mating bond between them Because she wasn't able to get pregnant.
 
But did the possessive Alpha really leave his real mate for that reason? Or he was forced to do his best to get her back?