My gf cheated on me and told me 2 days before her birthday, Am i insane for still wanting to celebrate?

So I've been dating her for a year, got a trip planed for 2 weeks time. Told her I love her multiple times during the year, bought her flowers/ theas, cooked her meals and still she slept with another man while I was out of town. I knew I'd be alone when I was out of town and from the beginning I told her to go out while I'm away to the clubs or at least to the cinema for entertainment. Instead she was just philandering around while I was away. <br><br>I'm a 28 year old software engineer, she's a 24 year old medical student. I don't know what really went on in that damned head of hers, while I moved heaven and earth for her, most of her friends can't even be in a real relationship because of how hard it is to get into med school in my country. Yet every time she knew I just really wanted her, she was being cold as ice, when she moved into my place she told me that she moved in to be with me, because she moved out of her mom's place to be with her boyfriend. So I was the second man she was living with. <br><br>She knew I'd break up with her if she'd ever cheated on me. I told her how much it hurt to be cheated on and I told her that the pain is so strong that they can't even look at the cheater. <br><br>I know this is going to sound insane but I'm still planning to celebrate her birthday with her because I know it will hurt her more if I leave her than if I just let her know that I still love her. <br><br>Am I insane?