Did your ex-boyfriend send the wrong message?

First of all, you will definitely not send the wrong message. Sending this message has the following meanings:

1. He misses you. This kind of missing may be related to his mood, or it may be related to what happened at the moment, such as being in a bad mood, quarreling with friends, and being awkward with his current girlfriend. Think about your kindness.

He was just lonely and accidentally thought of you, and sent a message to say hello, that's all.

He wants you back.

But I think the second possibility is mostly. You can see what he did to you after that!