I third (fourth?) the safe cosleeping suggestion. I honestly have no clue how anyone can make it through the first year bf without cosleeping. And once you've mastered safe cosleeping, you will notice wakings less and they'll take less time from your sleep at night. You can even cosleep for baby's naps and make up some sleep that way. Contrary to other advice, you don't have to bottle feed now, and I certainly wouldn't suggest nursing refusal to do so. I totally understand wanting some help with night feeds and if he'll take a bottle from your OH occasionally, that's great, but perhaps your immediate focus would more effectively be put towards minimizing the burden of the night wakings by adjusting your sleep arrangements.
ETA- formula use isn't effective at stopping night wakings. It might work for 1 or 2 nights if lo's tummy isn't upset those nights, but they get used to it after a few days and go right back to frequent wakings-- only on formula you have to prepare a bottle instead of popping out a boob. It's a developmental thing-- they go through sleep regressions around 4mo, 8mo, and whenever they learn a new big skill like crawling or walking. It will pass.