[Nessa Telrunya]

I think, in the case of Bilbo, perhaps he just didn't feel like getting married. That in itself is a lot of responsibility on someone, and maybe before his journey, he was that sort of hobbit. Before Gandalf showed up, he'd been portrayed as an ordinary hobbit, remember how horrified he was that such outlandish folk would be seen around Bag End?But after the journey, he would rather have been writing in his book, and he set Frodo up as his heir, so there was no need for him to marry just to have kids. Frodo, on the other hand, was stuck between being sociable and being with Bilbo. The older hobbit played a huge part in his life, and it wouldn't be surprising if he'd been Frodo's role model. If it hadn't been for him, Frodo would likely have not felt such a taste for adventure, because he would not have seen what good was possible to come of it.