Confused if I should have a second child

Hi, my husband (M36) and I (F36) have the sweetest 3 year old boy. We have been married for nearly 8 years and are financially comfortable. We initially didn’t want children but 4 years into our marriage we changed our minds. We love our son very very much and now we’re at crossroads about whether or not to have a second child. My husband is clear that he doesn’t want a second child at all because one, it’s a big financial burden and two, he doesn’t believe all siblings are close to each other (he’s not close to his sister). If you ask me, for my own selfish reasons I wouldn’t want a second child. First of all because I will have to undergo IVF. My first pregnancy was very tough, I’m traumatised to go through it all over again. Then managing an infant and a toddler will be the death of me I worry. My husband travels a lot for work, already majority of the parenting of my son falls on me along with managing the household and my career. My business is finally thriving. I had my biggest financial year this year and I’d hate to put the brakes on the way my work is picking up to have a baby. All this said, I can sense my son is ready for a sibling. He is a social little guy and actively seeks kids to play with. He inserts himself into other children’s play even if they are not welcoming him. He also needs a lot of human interaction and I think he’d really love to have it with someone that matches his energy rather than his overworked parents. I also worry that if he’s an only child he’ll miss out on such a big love of his life. I have an older sister and she’s my constant everyday go to for everything. I’m driving myself crazy everyday considering all sides to each option. I would love for you to weigh in with personal experiences and opinions. Thanks!