Why might I be scared to say I love you again?

This is someone I’ve been dating for a while. He and I have said I love you twice. I said it the first time early on but he said it back. Months later he initiated it and said I love you on his own randomly. And lately I’ve been compelled to tell him again but it’s hard. It’s not anything he’s done to make me think he doesn’t love me.

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And I want to state, nor do I have any doubts that I still love him. In fact, I’m more sure than before
Why might I be scared to say I love you again?
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