heartbroken for valentine's day

so I just found out my s/o was cheating on me in Mexico...he was out there for his brothers wedding and turns out he was even trying to introduce that girl to his parents..luckily his parents love me so much they immediately stopped him in his tracks...his mom told me that girl has nothing on me, that he would be back begging me to forgive him..I'm heartbroken because we were planning a wedding for August! I feel like my whole world is crumbling at my feet. 💔