Contrary to what romantic comedies and daring relationship stories might lead you to believe, having a crush on someone doesn’t immediately make you into a plot-critical, above-the-law main character who “gets the girl despite adversity.”
In reality, if you do end up developing a crush on your coworker’s husband, then attaining his phone number through nefarious means and start driving a wedge into their relationship, all you’ll get is a meeting with the HR.