Just because you find a man doesn't mean all of your life problem's will be solved. Gene clearly struggled with finding himself, making a place for himself in this world. And it was never guaranteed that he would ever come back. So it makes sense for them to not be in touch during the time skip. Yes you can stay friends with someone you were once in love with. But it's painful and not everyone can manage that. Their relationship was different and hence the weirdness.
Just because you find a man doesn't mean all of your life problem's will be solved. Gene clearly struggled with finding himself, making a place for himself in this world. And it was never guaranteed that he would ever come back. So it makes sense for them to not be in touch during the time skip.
Yes you can stay friends with someone you were once in love with. But it's painful and not everyone can manage that.
Their relationship was different and hence the weirdness.