A female classmate got married, had a child and had a bad relationship with her husband. Recently, she chats with me every day and often jokes that she misses me.

Looks like you should be interested in her. So you are also very sensitive to her jokes, and you will unconsciously catch her meaning of "there is something in her words". You really want to know what the truth is about her. You really want to know whether she likes you or not, and whether she wants to have an emotional relationship with you or a further relationship.

If you jump out of her marriage, you and she are in the stage of ambiguity and flirting, which really means "a little". However, as you know very well, her marital status is inseparable. You and her husband are so close, if they divorce because of you, you will be in trouble at any time; If she has a relationship with you, but she doesn't get divorced in the end (she has children, so she probably won't get divorced), then your situation will be very delicate and even embarrassing.

Therefore, the grass beside the nest is really not so delicious, and married women are not so fun. You should look before you leap and protect yourself.