Hey- mine is 6, and I really struggle with this. I think you should sit down with your partner and have a very frank talk about what support you need. His response to you was very callous, and unacceptable. He owes you an apology. You both have a toddler, and it is reasonable to come up with a plan together to make sure that everybody's needs are met. Your needs are valid and important. I suspect that his assholery might be coming from a place of stress as well (I hope that he is not usually like this to you?), but y'all are on the same team. He needs to help you come up with some strategies to take some pressure off.
What is your childcare situation? Are you the primary caregiver? Do you have help? What is your husband's role? Can you arrange for additional support?
Ideas for support:
Sometimes a friend or family member may be able to babysit for a few hours a week. You might be able to hire a tween or teen as a "mother's helper" while you are still home to help take some of the pressure off. There may be a mother's day out, or short term childcare place near you where you could drop your kiddo off to play for a short amount of time. Play dates with an understanding friend may give you some relief, as you child's focus won't necessarily be on you. If you don't hate the gym (I love swimming, and find the sensory aspects of it very relaxing), many gyms have childcare included in membership.
Things I've done to help manage overload:
I don't know if yours is old enough to understand a timer, but when mine was a toddler I started putting myself in time out. I would set the timer, and would let kiddo know that I needed quiet alone time until the timer went off. I would explain that it wasn't their fault, I just needed to help my brain calm down. We practiced this when we were both calm, to make it easier when tensions were higher. I use this regularly. It's very useful on days where I'm just having a rough time from a sensory aspect, or when I start to lose my patience during parenting. It's also a great lesson for kiddo, who now also uses quiet moments for himself as a self regulation tool.
Ear plugs. Almost all the time. I can still hear the kiddo just fine, but it's down several notches (loop is great). Noise canceling headphones over ear plugs helps if yours is a constant noise maker like mine. When they are playing independently, I will pop the headphones on, and let them know to get my attention visually or by tapping my arm if they need me. We started this around toddler age too. Sometimes I'll play tones I like on the headphones with the earplugs still in and it's very effective. I also used this during tantrums- I would say "this hurts my ears and I'm going to protect them", and then put them on.
We have worked a lot on consent and being the boss of our own bodies, and this helps with the CONSTANT TOUCHING that is part of parenting. It does take a lot of work and gentle reminders. Catch phrases have been helpful- "no-touch time" (set a timer), "face space" (back away from my face), "personal boundaries" (this gets used when I've asked them to stop doing something, like climbing on me, and they don't stop immediately). The catch phrases help normalize the boundary for my kid, they are said kindly, and they get easier with practice. They're also helpful for me because when I get overwhelmed words get hard.
Best of luck, OP. You're not a bad mom. It is ok to need support. It is ok to acknowledge that you're overwhelmed. I love my kid so much, and also parenting is just... a lot. I hope that I've shared something useful for you, even if it's just the knowledge that you're not alone.