 If you liked
Keroro Gunsou
|
 ...then you might like
Urusei Yatsura
|
In both series, Aliens come to invade earth, but get stopped by members of an earthling family. The aliens put then any earth conquering plans on hold, but instead lead their daily lives together with the humans. At least one alien develops a romantic interest in a human, which is a minor (Natsuki/Giroro) or major (Lum/Ataru) topic of the series.
If you are interested in interplanetary slice of live, you may try these titles out.