Little boys with different personalities?

I have two little boys. My oldest is 3 and my youngest is 8 months. In some ways they are very similar, but in others they are completely different. One major way that they are different is the way that they show affection. My youngest is a big cuddler. He would love to do nothing but sit with me and snuggle all day long. It's very easy to show him love. My oldest though is a little more complicated. He is not a touchy feely person and never has been. He fights being held, has to be bribed to give a kiss, and never ever wants to sit and be cuddled. However, he is a very loving child. He is generous and caring. I'm always trying to find ways to SHOW him affection that he is comfortabe with, but it is a challenge compared to my younger child. At this point my older son is seeing how much my little one gets cuddled, and he is jealous. But he won't let us do the same with him. I'm worried about him feeling like we are playing favorites, or thinking we don't care about him. Does anyone have suggestions for how to handle this? I'm an only child myself, so the world of siblings is new to me. Any advice or insight would be greatly appreciated. Thanks!