I'm sorry to say, but I must admit, that posts like this make me sad. Maybe I'm just "old-fashioned" but I'm of the firm belief that marriage is for life. I don't know how long you've known each other, but obviously you both loved each other enough to get married, and agree to spend your lives together. And now, after only a few months, you're already deciding that you're going to "cheat on her or break up with her"?!?!?! I'm shocked! Do you really want to throw away everything you feel for her, because you currently feel unsatisfied, instead of fixing it, so you can both be satisfied?
The first thing you need to understand is that marriage is not a fairy-tale suited to pander all of your desires. It is instead a commitment between two people to live their lives in devotion to one another. That means you devote yourself to her, and in turn, she to you. When you don't get exactly what you want, you don't just say "screw this... I'll get it somewhere else." Instead, you should consider expressing your desires and concerns directly to your wife, so that the two of you can work through them together! When the two of you can do this effectively, you'll always end up with a stronger relationship between the two of you, as well as a deeper trust, better communication, and a closer bond to the one you love.
There are a few things to consider in a situation like this. First is communication. Do the two of you have open lines of communication, where you feel comfortable telling each other ANYTHING and EVERYTHING in truth? If not, start there. It'll go a long way to establish trust that will make her feel more comfortable, as well as open avenues for discussion about things like your sexual frustration. PLEASE NOTE THOUGH... I am NOT suggesting that you just go marching into a room and tell her how you think she sucks in the sack. I'm talking about encouraging and tactful conversation in a non-threatening, and non-accusatory environment. Communication used effectively can be one of the best building blocks for your relationship... but used incorrectly, can quickly lead to a bottled-up and resentful spouse with no desire to be amorous, or cater to your wants and needs.
Additionally, the best way to GET a good spouse, is to BE a good spouse. Even if it's difficult at the time, and especially when you don't want to, that's when it's most important for you to demonstrate what a good spouse is. The more you do it, the more it'll be reciprocated.
Don't get me wrong, I'm not trying to point the finger, or play the blame game, or call you a bad spouse. Everyone has their moments. Lord knows I've had mine! We all make mistakes, and that's part of marriage. It's what we do with them that makes a great marriage or a failed one though.
Once you two have established the communication, the bond, the selfless attitudes, and the devotion to one another, things like your sexual frustration WILL be taken care of. You'll be able to easily talk about it, you'll have the desire to suit her needs (once you know what they are), and she yours. NewMe gave some great advice in her post, so I won't go retyping all of it, but be aware that these things do take time! And when you stick with it, the time spent is WELL WORTH IT!
Don't think of it as being let down now... instead think of this time as a time of learning experience. You are still learning about her and what she likes, and she about you. As you learn and explore each other together, things will get better.... better than you could ever imagine.... and DEFINITELY better than someone new each time you are let down.
Sorry this got so long-winded... I'll step off my soapbox now.