Mom advise

I need help my three year old wants nothing to do with his dad. If his dad wants to play with him he just yells no dada. My husband is feeling hurt by our sons rejection. He only will spend time with him if I'm not around. I just had a baby so dad is not working to help me but my son won't spend time with him. I don't know what to do to help them bond again. Please advise, any one else experienced this with their kids