Thank you for your email. I hear your concern that you may be setting your son up for failure.
On the contrary you and your wife seem to be tuned in to your son's needs and allowing him to cuddle with you in bed is giving him an opportunity to attach especially if he has been separated from you all day. Being close to you and your wife makes him feel safe, secure and loved, thereby better equipping him to cope with difficulties in life later on, and therefore less likely to feel like a failure.
Some children are more sensitive and need to feel close to their parents, while other children are more independent. Provided your eldest son is able to separate from you and can do things for himself, as it appears he is able to, there is no need to worry. Avoid comparing your boys, as even though they are brothers they can have completely different personalities and needs and it is important to meet their individual needs. Some children don't like too much physical contact re: hugs and cuddles.
You can invite your youngest son to cuddle in bed in the mornings, especially on the weekends, but unless he expresses a need to come to your bed and he is receiving lots of attention from you at other times, there is no need for concern.
Wanting to be close to your children is not selfish and you can ensure you are giving your boys the same amount of attention by spending 10 minutes one on one time with each boy every evening telling them how much you love them as well as how special they are to you. In addition, you and your wife should arrange an individual date with each boy once a month to do something they enjoy.
Continue trusting your instincts and those of your wife and tuning into the needs of your children.