Dear Annie: I’ve been in a committed relationship with my girlfriend, “Sarah,” for three years.

We live together and have been discussing marriage. However, I recently discovered something that’s left me feeling confused and betrayed.

While cleaning out our closet, I stumbled upon a hidden stash of letters and mementos from her ex-boyfriend, “Scott.” The letters were deeply personal and intimate, expressing a level of passion and emotion she’s never shown with me. They dated for four years before we got together, and she’s always insisted that she’s completely over him.

I confronted Sarah about it, and she admitted she occasionally reads the letters but swears it’s purely nostalgic.

She says she loves me and wants a future with me, but I can’t shake the feeling that I’m competing with a ghost. It hurts to think she might still have feelings for him.

Now, I’m questioning everything.

Am I just a placeholder for her true love? Is it normal to keep such mementos, or am I right to feel betrayed? I don’t want to end our relationship over this, but I also don’t want to live in the shadow of her past. What should I do? — Thrown off by My Girlfriend’s Past

Dear Thrown: If you really love Sarah, you shouldn’t have read her private letters without her permission.

However, it’s not uncommon for people to keep mementoes like these from previous relationships — not because they still harbor feelings for an old flame but, as Sarah said, out of nostalgia for something that was once important.

Sarah’s relationship with this old boyfriend ended for a reason.

Be transparent with her about how this discovery made you feel, but believe her feelings for you. You can’t move forward together if you’re constantly looking at the path behind you.

Read more Dear Annie and other advice columns.

“How Can I Forgive My Cheating Partner?” is out now! Annie Lane’s second anthology — featuring favorite columns on marriage, infidelity, communication and reconciliation — is available as a paperback and e-book. Visit Creators Publishing for more information. Send your questions for Annie Lane to [email protected].