husband's ex

So my husband has a Facebook that he hardly ever uses, but I have the password and check it sometimes. Yes, I know. Judge if you want I don't care lol And his ex is always trying to contact him. 3 years ago when we got married she messaged him, when I got pregnant she messaged him and she's always messaging him on his birthday/holidays. He never responds or anything so I haven't said or done anything, but I'm just a little bewildered honestly lol She tried to friend me and I denied it. Ive only met her once, but she tries to create drama all the time and tried really hard to break my husband and I up when we first started dating. I think she just wants to be friends, but he never says anything back and I'm kind of surprised she's still at it 5 years later lol Has anything like this happened to anyone else?