<human>: Posting for my sister because she doesn't have an account. So, my sister has been dating this guy for a few weeks now but he broke up with her because he got a job and has all these other commitments and thought it would be unfair to her to not be able to see her and stuff. I thought it was fair enough and thought he was being reasonable.   

Now, here's the weird part. He was saying that they can still be friends and stuff, whatever, trying to keep her in his life. Recently though, he's been messaging her and flirting with her and still acting like they're kind of in a relationship, saying he wants to kiss in secret and stuff. Here's how their conversation went:  
Him: Do you know what I always imagined us doing?  
Her: What  
Him: Us meeting up then me slowly touching your cheeks, brushing your hair away and then you know kiss you, and possibly make out xx  
Her: Tbh I had a similar image  
Him: Did you rly? You know we could still do it, just no one would have to know xxx  
  
Now, I care about my sister and a number of people, before they started dating warned her about him but we just thought it was a bunch of jealous guys (some of them used to/still do like her) and he made her happy so they dated anyway. What concerns me here, after reflecting upon this is that I feel like he has another girl lined up to date and wants to go public with her, but still have my sister in secret. It just seems weird that he wants it to be in secret. I really don't want her to be hurt like she has been in the past, so is this a legitimate concern?

Condense the text into a few key points
<bot>: Sister's boyfriend broke up with her but wants to kiss in secret. I think he likes another girl and wants to go public with this girl but wants to keep my sister. Thoughts?