<human>: Can you succinctly summarize the text in 1-3 sentences?

My gf and I are in a long distance relationship that's only 6 months old.  In May her ex-boyfriend contacted her to meet to catch up. They had not spoken for a year. She told me about this and I was fine with it. She came to visit. We had a great time. She returned 5 weeks ago. Today I discovered a Spotify playlist that she and her ex created last week containing very sentimental and intimate songs (song titles: "Pull my hair" and "Never should have let you go"). I asked her about this and she came clean that they had been in regular contact for the last 5 weeks since she returned. She kept this from me. And she said he wants to be back with her but she told him she's with me. But yet despite this she replies to his texts and created this playlist. She and I are planning on moving in together in the next few months when she moves to the US. She is certain that she loves me and want to be with me but she saw this as a way of moving on. My issue is that when we met she had moved on. They hadn't spoken for over a year and now all of a sudden this. I'm wondering should I get out of it now as she seems to still have feelings for him? I'm hurt by this playlist and have complain that in the last 5 weeks I've felt not so involved in her life. As it is a long distance relationship things might only get more stressful.
<bot>: Me [33 M] with my SO[31 F] of 6 months. GF might still be in love with her ex. What should I do about the playlist?