The very qualities that attracted you to your partner in the beginning -- their unusual, individual, even bohemian aesthetic, for example -- could end up becoming the wedge that drives you apart. You're just too different to make this last long-term, even if you wish you could commit to each other. You're looking for very different things, and they, especially, likely feel pressured and restricted by the relationship.
Are you just in this because you're trying to do what you think you're supposed to -- what your parents want you to do, for example? Some people get married and have children more because they think that's what's expected of them than because it's really what they want to do, deep down in their hearts. You could easily fall into this trap, and might push toward that end despite the fact that the two of you don't match up well enough to merit a long-term bond. And your partner definitely struggles against these bonds of expectation and traditionalism. They feel like they're going to suffocate under all that control, those rigid parameters of what a love relationship is supposed to be or lead to -- and they buck the pressure in the only way they know how. If the relationship means something to both of you, you could develop a pattern of frequent breakups punctuated by brief reconciliations, but you always cycle back around to the fact that you just don't work out that well together.