I just want to know why all of a sudden the good/nice guys are popular on valentines day?

Because you know most women love dating the and i know a girl who's like this. She has a BF and he NEVER DOES ANYTHING FOR HER.. He decided for valentines day, he would rather spend it with his buddies in vegas instead of her, so now she is alone at home and calling me asking me to hang out with her sunday. All she's going to do is ***** about her boyfriend in vegas and moan about him not being with her which i don't want to hear. She picked him over me in october, I have a good job, never been in jail, respectful to women which i know all those qualities are a TURNOFF to women but so be it! Him = doesn't have a job, not trying to look for a Job, always ask her to borrow money, smoke weed whenever he can, went to jail for egging cars with his friends and she ended up choosing him over me, so i said ok fine, haven't talked to her in 4 months, after that, now she is texting me asking if i would like to go to dinner and i found out through a mutual friend that her boyfriend took off to vegas with some of his friends and that's why she texing me.. How should i tell her i'm not interested or should i just not return her messages or calls?