Hi,
The English would read more correctly as written: I am very happy because I am in love. However, it could be written as megastein has indicated that a man is happy because he loves or is capable of love. The most important thing here is to translate into English the INTENT of the author, not only the dry word for word translation.
Hello to both!
I think megastein is right but this kind of statement is usually said to express "being in love". the literal translation would be: "i am very happy because i am loving" (it's not obvious what s/he loves but most probably "being in love" is implied). Thank you dramati!