..She's Mine, But Not Exclusively..

I've been with Sarah for seven years now. We started out as high school sweethearts but transitioned into a mature relationship once we both hit eighteen and beyond. These days, we're not strictly monogamous... she still has her own life outside of me. She's mine in the ways that count, morning cuddles, late-night chats, planning our future together, but I understand her need for variety and independence. I'll be honest, there have been a couple times where my insecurities got the better of me... but Sarah always reassures me with how much she loves spending time just with me. It's hard to explain, but it feels right this way. So many friends are in tumultuous fights about fidelity and boundaries, but we've found something that works... Still, sometimes I wonder if there should be more of a commitment from her side. Am I the only one giving here? Is this normal for a long-term relationship like ours? ...what do you all think?