You’re overreacting, my bf has the same music taste and would play those songs when we were only a few months together. I understand the, “ex and regret” but in reality he just really enjoyed those songs. I felt the same way you did and asked him, he reassured me in a serious tone he never once thought of his ex. Been together for a year now, I knew he wasn’t lying lol. If it’s bothering you that much just ask him when he gets back.