Ex husband and I were together for 15 years, divorced for 3 now. He’s been dating a much younger woman for probably 8-9 months. We’re mid 40s, not exactly sure how old she is as he won’t say but I’m guessing around mid 20s. He hasn’t brought it up yet but I’m sure he will soon. I don’t want her to meet my kids. He’s mentioned that it’s not a fling but I just don’t think it will work and I don’t want them getting attached to her and then being upset when it ends. Am I being unfair? Thinking too far ahead?