How do I measure up to my cousin and get as many girls?

Looks aren't everything. You need character and personality development. You are competing and knowing you are weaker in the looks area than your cousin therefore, your inferior side comes out. He is confident and doesn't have to try hard but you are trying too hard. Kind of like a shoe salesperson who is confident in their ability vs a newbie trying too hard to sell. People can read him. Be relax and confident in your personality/intelligent having values vs knowing you don't have experience and looks when COMPARE with your cousin. You need to be you and stop trying so hard because your mindframe has set you up to feel inferior because you are comparing yourself who has achieve more ( not that it is good achievement with your cousin, he could bag himself a gold digger or std). IMHO, I am not misjudging you, I am giving you a straight hard answer.

Tell him that you go for quality not quantity

Honestly, you shouldn't be worrying about numbers of woman you sleep with for these reasons
1) that is demining to woman and offends us
2) that hightens your risk for STDS
3) hightens your chance of getting a girl pregnant ( even with birth control happened to me twice so don't think it can't happen)
4) sex should strictly be something between a man and a woman who are married
I think that sums it all up the risks aren't even worth it. seriously though and I apologize for being this blunt, grow up and mature a little bit. Instead of worrying about how many girls you can get you should worry about finding that one girl that you can't live without. Us woman are not objects for your pleasure or should be used for another notch in the belt or to be used as a competition between men. I am sorry if these words aren't what you want to hear but this is what I feel you needed to hear.

Well since you're so shallow about looks (enough to compare your cousin's hookups to your ex? Wow.), you know what the problem is. You're not as hot as him. You seem to grasp this concept quite well with women, but not yourself. Work on your looks and maybe you'll get more girls. Although I sense your personality, shallowness, and extreme competitiveness over who can screw more people is what's ruining this for you.

Tough guy game or narcissism game.
Both work well.

I had a similar problem during school with my best friend (although I didn't think he was especially good-looking, but the girls did I guess). I often tried to avoid him because I began to despise him for being so popular and successful with girls. Now, none of these girls are girls I would have dated (not my type personality-wise), but with us being two competitive guys during college, I was clearly 'losing' in the ladies' man department.
I know the feeling of wanting to be the guy that girls just come up to and offer their phone numbers, but it isn't going to happen at this point. What you should do is find a great girlfriend (easier said than done, I know) and then not worry about how many tramps your cousin has bagged. If it makes you feel better, maybe keep avoiding your cousin for now until the whole thing blows over.

You are going about this the wrong way. You should welcome his popularity with the ladies. Why, because most pretty girls have friends, and their friends have friends(hint: that's where you come in if you play your cards right. How do you play your cards rights you ask; by asking your cousin to look out for opportunities to introduce you to their friends, and genuinely supporting him.

It always amazes me that guys would rather hate a guy that is able to pick up women easily, rather than take advantage of the opportunities that he may afford them.

I was in a close to identical situation with my cousin. He initially resented my success with the opposite gender and then began to hate me. Needless to say, I kicked him to the curb because If he resented my success, then with out a doubt, he would have tried to tear it down.

He's your cousin, man. This is trivial; there's more to life than beating him. When you're older and settled, you're likely going to wish that you would have focused on enjoying the time that spent with you're cousin, and all of this will be trivial and thus regretful if you fall out because of your spite towards him. It's not worth it!

You know, for someone that's studying medicine, you sure do know very little about "the contrast effect."

I strongly recommend: link

I remember when my womanizer uncle took me with him one day as "bait" (i.e., to have something to attract women in their late 20's and early 30's to our group). Needless to say, the plan backfired. He had absolutely zero success with anyone the whole night. Women were confronted with a choice: (1) young, good-looking, non-sleezy, up-and-coming lawyer and accountant, or (2) older, average-looking, superficially charming and sexually eager MBA executive. Picking (1) would be fun, whereas picking (2) "in that situation" would make them feel like a whore, a regular street prostitute simply electing to sell herself to the highest bidder - a negative feeling each sought to avoid. And, since I didn't share his interest in casual sex for sport, we all walked away unhinged that evening.

Next to your cousin, you're "the short one," the "less attractive one," and the "less hot one." You work wonders for your cousin, however. You are the short yard-stick women unconsciously measure him against, an immediate reference point you provide for him to shine.

For starters, you should try to formulate a social group of a few men, maybe one or two, who are also around 5'8", also about physically average, and just a tad bit less attractive than you. Why? Because "the group" as a whole must still be "worth" associating with.

Now, in "that" group, you are the alpha male. You are the "better" looking one, and you have the "highest" expected future earnings potential. You are the male with the higher "relative" social status and power. Thus, given the choice, or rather, presented with the choice of socializing on a deeper level with any "one" male in the group of males, females will "prefer" to socialize with YOU.

Now, the bigger issue is your obsession with keeping "score."

You're still a virgin, so I don't blame you as a man. It's very important to a man's psychology to get rid of his virginity. But, after that happens, you'll realize that sex is really not that amazing. Sex is actually pretty crappy unless it's with the right person. As a physical activity which rewards you with the release of pleasure hormones, masturbation is superior if you do a cost/benefit analysis. Yet, as an "emotional" activity, sex "with the right person" (because of the relationship the two of you have built together) is far more rewarding. To get there though, you obviously need to have sexual experience "together," and build sexual comfort. But, you'll find yourself empty, alone, and even more unfulfilled if your sole or primary aspiration is to keep "score" with your cousin.

Keep some distance betweenn you and him at parties You can 'hang out' without sitting next to him all the time, where you'll be exposed to his popularity.

There's more to life than sleeping with a lot of girls. If you find one that really likes you, that will be more than a lot of guys ever have. Few of these girls really like your cousin, you know.