Co sleep to crib

Me and my husband has pretty much not seeing eye to eye when it comes to transitioning our son to his crib. It makes me cry to hear him crying to bad at night so I would always come and save it. It’s almost like I’m co dependent on him and it’s hurts to make him go in his own bed. Also he would nurse at night which is also another reason why it’s so hard on our baby. Well now it’s starting to affect our marriage. What do I do? What can I do to feel more comfortable? How do I get my baby to start sleeping in his bed? I bought the Merlin’s dream sack do you think this will help?