Extreme levels of the type "oh you are my whole world" are somewhat unhealthy in that it betrays that the person giving that love may have some underlying emotional issue or void that they are trying to fill.
Now men are kind of different to women in that they are not uniform in their reactions to this type of love. Actually they are divided in two categories. Those who would appreciate a total dedication (without being creeped out) and those who would exploit it. If the man is more "beta" he will tend towards the first category of appreciation/devotion. If the man is more "alpha" he will tend towards the second category of exploitation.