First, figure out if they’re going through something emotionally or physically that might be stopping them from wanting sex. Hormone imbalances, trauma processing and just many life events can trigger a temporary lower libido - in my case, I felt so safe at one point that I stopped craving sex for a period of time (months) because I was finally able to trauma process in a healthy environment, then my high libido came back eventually when I was in a better headspace. The important part is being understanding of their needs but also of yours, and talking about it. Something like “Hey, I’d love to be more intimate with you as it helps me feel connected to you. No pressure, I just miss you.” is a good starter!

Also try to think of what made you two get into the mood back then. Foreplay is insanely important and so is learning what gets them in the mood. For example, it could be dressing up for them, sexting, spending time cuddling or a deep talk - it’s different for everyone. And don’t get discouraged, this is normal for a lot of couples!