Your feelings are exactly why it is important to discuss this prior to marriage. I would also note that while sex is of very high importance in marriage, it may not carry the weight it currently does in your thoughts right now, in the future. When we are young sex holds a disproportionate place of importance, one that it will not always hold. Having said that I want to empathize the importance of finding someone compatible with you, someone who has similar interests and beliefs.
For example finding someone who feels similarly about the importance of sex… There certainly are some who may say this is rather shallow. However for my husband and myself marital intimacy is of great importance, our marriage relationship in general is of great importance. I strongly feel that my relationship with my husband is the single most important relationship I will ever hold here on earth, before my children, parents, or siblings. The point I am trying to make, is that my husband coming to me with desires for intimacy (sex) that he feels are unmet would NOT be met with feelings of being burdened or annoyed! Quite the opposite in fact! In marriage we are called to serve the other, this includes sex among many many other things like packing lunches, folding laundry, making dr appointments, back rubs, picking up dirty socks and towels… I want my husband to come to me with his desires, I want him to feel fulfilled as well as desired by me. This is why communication is very important! Hope this helps… God Bless!