We had the same too. I introduced a dummy in the end, it just helped him to settle - half his sucking was definitely for comfort. He only needs it occasionally to help him settle to sleep. I don't think it's recommended with Bf'ing, but hasn't caused any problems here and has actually been a life saver.
Hugs lovely. Those first nights are torture. Dh slept (and still does mostly!) on the sofa so at least he had a full nights sleep and could then be up with DS1 the next day and I could catch up on sleep when baby was sleeping.
It does get MUCH easier, honestly xxx