Well what your experiancing is 100% normal and healthy! Your son is at an age where they start to realise a differance between mum and dad. As a boyhe is drawn to his daddy because they share something the same and he is realising that. Its really important at this time to make sure you encourage a strong bond to be built between father and son-this will make for a healthy relationship in years to come when it will be extremely important for your son to feel like he can trust his dad.
At the same time yes you feeling rejected is normal but its very important you dont take it to the level of resentment. He is not doing it to hurt you. You and he have a bond from the time he was born that cannot be broken. He is going to go through many phases over the coming years of swapping and changing between the two of you. My two year old wouldnt have a bar of me when our daughter was born and this went on until just recently(our daughter is now 9months)
if you can, try and veiw it as healthy and a good thing-this way you get more sleep at night, you can really make a strong bond with your second baby while your husband can help out with number one!
If you dont push him or make it a point of tension he will come to you-just let him do it in his own time-let this be a learning curve for future years to come-the harder you push a teenager to talk to you the harder they keep thier mouth shut-its kinda the same!
Good luck and from experiance i can say its normal, its healthy and not a cause for resentment!
Kathryn - Zack-4, Toby-2 & Molly 1