I just feel so bad for my DH. Liam is a full blown mama's boy. He loves DH but has a serious issue with doing anything without me there, especially lately. I am Liam's primary caregiver and DH travels for work which doesn't help but I just wish that Liam would accept him a little more. Right now DH is trying to get him ready for bed and I can hear "Mommy! Mommy!" which is bugging me to no end because DH is perfectly capable and tries so hard! I never interfere unless DH wants me to, though, so there will be no "rescuing".
Anyway, when does this phase generally end? I am going a bit batty here.

Re: When Does The Mommy Phase End?
DS2 - Oct 2010 (my VBAC baby!)
My DS is also a mommy's boy. So much so that only Mommy can kiss boo boos, and he will only eat Momm'y pizza (Not Daddy's). In fact, He gets upset sometimes when DH gives me a hug!
I'm a little worried about what will happen when we have baby #2 (eventually!) My niece was holding my hand while we were out last weekend. DS kept trying to push her hand out of mine.
DS1 is like this with me. It is getting better now that he's older, but he still generally prefers me to do everything for him. You are doing the right thing by not interfering. They have to develop their own relationship. My DH is really good about playing with DS1 now, and he really enjoys that. It used to be that if he asked for a drink and DH went to get it he would say "No! I want mommy to get it!" I would just say, "No, either daddy gets it for you, or no drink." It will get better. I know it can be hard on the dads though.
DS2 is like this too, but not to the extreme that DS1 was. He is much more willing to go with DH.
Yeah probably this, lol!
But I will say that the past few Sundays DH stays home w/DS while I go out and get the paper, shoot through Starbucks and wander around Target or WalMart or whatever... just be by myself. In the past when I have left DS would stand at the gate by the back door and cry, now he barely notices me leave. I give DH a kiss and say "OK mommy's going out for a little while give me kisses" and DS will do the same and continue playing. It's our new routine and it's working great!
We don't have any family and very few friends here so it's the only time I get to be away from him which I think we both need at this point sometimes. It's made a big difference in both of us. I know you said your DH travels though, are there any close family or friends that you can leave him with? IMO that makes it more important for him to have some 1 on 1 time with him so that your DS knows that daddy is a capable parent. MY gf goes through this w/her DH (who doesn't travel but isn't home with the kids a ton) and she also does what I do occasionally, she's trying to get her 2, 5, and 8 yr olds to see this...