I love you, on its own, is nice but it’s more powerful when you are specific. Love means something different to everyone. Get clear on what it means to you and what exactly you love about each other.
The love in a secure-functioning relationship is one that comes from daily evidence of devotion and protection. It’s a stronger love than you might otherwise be used to because it’s earned out of respect from doing for each other what nobody else would do. “I love you” on its own is nice but it’s more powerful when you’re specific about what you love about each other.
But the main point is this: the strength of your relationship can only be determined by the two of you. In spite of the inevitable conflicts in a committed relationship, If the two of you feel safe, loved and cared for, that’s all that matters.