Hi CDx dont panic this feeling is completely normal, I often get what I call the seesaw, you have a thought pop into your head (for me it was expressing is getting painful and yesterday she brought up a whole bottle which made me cry and say things like I cant do it anymore, its too painful), then talked to OH and he calmly said well its upto you but you are giving her something only you can give and she needs it to which I then broke down again feeling guilty for wanting to stop expressing and not wanting to refuse my baby girl anything..afterwards was completely fine and wondered what on earth I was upset about and so can only say they are strong powerful emotions that you have to acknowledge, deal with (discuss/cry whichever) and move on from.
I know how you feel about the all day thing, my hubby is off work atm but setting up in business by himself (some would consider us daft with a 6wk old lol) and whenever want to do things by myself (which is only occasionally) he reminds me that he needs to focus on getting busy prepared and he doesnt say it is an accusing way as he acknowledges I need time to myself much like your OH suggesting swimming, massage etc but its still hard cos when you're away your clock watching, constantly txting to c if lil one alright etc etc...but I hear you loud and clear, sometimes when he's out and about doing things I have one thought ringing in my ears (Im the one holding the baby), its matter-of-factly thought though not like resentful or anything but it is true and have now started taking her out on my own etc to keep us both sane (fresh air for her, exercise, fresh air and escape the house for me lol)...sometimes when they are non stop demanding it can be hard to not let out your frustration and would have thouight the same as you re: bathtime (i only wanted 5mins would be ringing round my head) but unfortunately our lil ones dont understand this concept yet and are still adapting themselves to having to ask for things like food, comfort, warmth... have you tried bathing with him with you in the bath? I am keen to try this at some point but atm hubby likes to join in with weekly bathtime so over the side of the bath it is for now but also considering taking her swimming and wondering how to handle the shower aspect of it as cant leave her unattended and not sure how Id manage holding her and showering at same time lol...oh well we'll figure it out...
at the end of the day CDx your OH is being understanding about it which is what you need so dont be afraid to lean on him occasionally and discuss his hobbies and how you want to do something similar, set something up thats regular as I dont know about you girls but unless I have set things in the diary each day just merges into another...its good to have things to look forward to even if it is simply a weekly walk or trek to the shops...