1true - it can feel overwhelming when you have a baby behaving like this...but it is normal and actually welcome in a baby who had a slow start, because he needs to make up for lost time. His needs to be in your arms and close to you, feeding a lot, are important ways of establishing a relationship on the 'outside' with someone whose taste, voice and smell he is familiar with from being on the 'inside'.
Giving formula at night seems a tempting prospect, as does expressing, but there are downsides which you need to know about before you do them.
Your milk supply is not established, and a bottle of formula or ebm given in order to stretch the time between breastfeeds may have an impact on your supply. There will be people for whom this did not happen, but you cannot tell in advance if you are going to be one of them. You could, of course, express at the time your dh is giving the bottle (your body will 'think' it's the baby and supply will be protected) but that doesn't make much sense if the point of the bottle is to give you a break.
The other downside is that a break of several hours between bf will ensure very uncomfortable breasts for you - it increases the risk of mastitis, too.
At the moment, the best help you can get with the bf (IMO) is to do all the stuff you would do if you weren't feeding - so any housework, cooking, shopping and so on is absolutely not your job . You are doing a wonderful thing, building up your son's trust and confidence in the world as well as nourishing him Anything else is less important.