In American TV shows, the phrase "I love you" is always used between parents and their children. To be honest, I've never said to my parents "愛しているよ/ I love you" although I love them. If I said that, they would be so surprised that they would start worrying about me. As far as I remember, they've also never said to me ” 愛しているよ” although I've realized that they love me very much.
In Japanese culture, ambiguous expressions are often preferred, so Japanese people subconsciously try to sense what speakers imply even when they don't imply anything. Japanese people still tend to prefer expressing themselves and being expected to sense others' feelings without words. When Japanese people express how much they love their lovers, they use various expressions based on situations. I guess that these backgrounds make 愛しているよ a special phrase. I'm sorry I can't explain it well.
PS: Actually, "大好きだよ/ I like you very much" is much more common among couples. Given that and considering nuances 大好きだよconveys, 大好きだよ might be equivalent to "I love you" among couples.
In Japanese culture, ambiguous expressions are often preferred, so Japanese people subconsciously try to sense what speakers imply even when they don't imply anything. Japanese people still tend to prefer expressing themselves and being expected to sense others' feelings without words. When Japanese people express how much they love their lovers, they use various expressions based on situations. I guess that these backgrounds make 愛しているよ a special phrase. I'm sorry I can't explain it well.
PS: Actually, "大好きだよ/ I like you very much" is much more common among couples. Given that and considering nuances 大好きだよconveys, 大好きだよ might be equivalent to "I love you" among couples.