A slightly different way to consider this might be to look at the your values house (2nd). I think this is kind of a lynch pin in this particular scenario for you.
You value independence, stability, permanence and structure. These are things that I integral to you and how you live, therefore we can see how this might create a conundrum for you in the relationship department based on your rising sign and moon.
Your ASC/DSC axis shows a person that wants to live life out loud. This is a person with an inquisitive spirit and thirst for life that will not be easily quenched. However, your values show you that in order to have the life that you want, you need to do things on your own to make sure it plays out YOUR (the 'right') way. You don't feel like you can count on a partner to provide for you so you do it yourself. This also means that these are things that you value in a partner as well. If this is the crux of a person's impetus to life its easy to see how a person (you) might feel like there is no room for a partner. In short, you value your independence and any sort of interdependence could be seen as a bit off putting and something that could lead to disaster down the road if not carefully navigated and God knows Sagittarius and Gemini are not known for 'caution.'
So why do you keep hearing that you shall get married? Let's look at the houses that bring marriage to mind. These for me are the 4th (home) and the 7th (our partner). Some would say the 5th, but I maintain this has more to do with attraction and infatuation than a solid relationship.
Your 4th house (using whole signs as I do) is where we find your sun. Your focus for yourself is creating something solid. A home base to work from and a place to feel secure. You want to explore your roots and literally put some down. This shows a person that is more interested in an inner life and is closely (or longs to be) closely connected to a family unit. This shows a person that can in fact settle down and adapt to a traditional role rather easily under the right circumstances (ie, finding a good balance between interdependency and independence which is absolutely doable).
Your 7th house is ruled by Gemini which is in turn ruled by Mercury which happens to also be in the 4th house in conjunction to the sun showing a strong tie between the two though the aspect is separating. This for me shows a person that is likely to get married.
Finally, moon in the 7th shows a person that kinda needs partnership. My boyfriend has this placement and though he is ridiculously independent, he has always had a partner. I'm just the first one to come along that allows him to maintain that independence and still feel loved and balanced.
I would say that marriage is definitely in the cards for you if you so desire.