In terms of the individual, I think that yes it does. Definitely. But, in terms of the relationship and the dynamics of the relationship... it depends on whether those feelings are reciprocated. You can't
make someone love you the same way you love them. But you can love them unconditionally and hope that they'll come to feel the same way. If there's a spark there, it may take the wind of time to breathe life into it and turn it into a flame of desire.
However, if two people are in love with each other, that is a force that is pretty hard to beat by anything this world and this life has to throw at it. You strengthen each other, the relationship becomes synergetic... each challenge serves only to remind both people how much they love each other and how they can overcome everything because of the connection they have with their love.
As Jay pointed out, sense of self is relegated to the background in favour of devotion to the object of your affection. Doing everything you can to make them happy, to see that beautiful smile and the light in their eyes shine just a little brighter... that is one of the best feelings there is.
Those are my thoughts, anyway.