My wife and I met in college, we are 41. I’m not jealous about her past partners. She has had her old prom dress hanging in the back of her closet forever. I’ve never given it any thought. Until, two weekends ago, my wife’s friend came over and they were in the kitchen which is open to the living room where I was, talking about taking the friends daught shopping for a prom dress. My wife says “I still have my prom dress, let me get it and show it to you.” She returned with the dress and she showed it to her friend and her friend made a comment “oh, no, it has spots on it” and my wife says “oh, yeah, my date wade a mess! I should have taken off before we did it.” The friend says “ew!” And my wife laughs and they keep talking about shopping etc. Later after the friend leaves I am in the bedroom, and my wife comes in with the dress, and holds it up in front of her in front of the mirror and says “I loved this dress, I wish you could have taken me to prom we could have got dirty in the limo”. I said “hey, I don’t feel comfortable with another guy’s cumstains in your closet on that dress, have it dry cleaned” she said “what! You never cared before! I have good memories of that night, this is just memories, don’t be jealous, I won’t have it cleaned.” I said “I don’t care that you had sex with other guys, I don’t care that this guy came on the back of your dress, I don’t want another guy’s cum stains in my house, get it cleaned.” She said “no, you’re overreacting!” 
It’s been awkward ever since. It’s still in her closet. I brought it up again yesterday while she was in her closet “are you going to get that dress cleaned?” She said “I don’t think so, don’t be jealous”. I have talked with her since. 
