I think you need to separate a few different issues here.
First, your business. You are the boss, which is great as you call the shots and have nobody dictating your hours physically in the office or your working arrangements. You just need to make sure that your employees feel happy (so paid on time, good flow of work, admin up to scratch, pleasant working environment, you being available to them when needed) and that the work keeps coming in. You say that the business would not survive you taking the time off, but it is good business practice to think about contingency and succession planning anyway- what if you had an accident tomorrow? You’ll have all your TTC time plus pregnancy to start doing some succession planning, maybe training up one of the staff to deputise your role.
Then there is caring for your baby during the first year of his or her life. Have you sorted out in your own mind how you feel about breastfeeding? This is not the place to discuss the arguments for and against, you’ll find endless resources elsewhere for that. Breastfeeding adds a whole extra logistical element to the arrangement that you need to take into account. Other than bf, your husband should have no problem with any of the rest of it and, as others have said, if he is willing then it seems better for him to do it than to employ a nanny.
Don’t forget however that you might feel you are missing out on bonding with your baby/toddler if he does the lion’s share. Yes, millions of Dads work full time and bond with their babies excellently but I think that the parent who is at home would usually agree that they have enjoyed the opportunity for so much time with their child. That said, with you being the boss it looks like you could have best if both worlds by working less than full time while DH is the main carer.
Then there is your idea that maternity leave will help you make friends. I can only speak from my own experience but I found that to be a myth. We made a few friends at NCT classes and I hung out with some of them after the baby was born and they are still friends. However, despite going to all sorts of baby groups and classes I barely ever got to more than nodding acquaintance level with any other parents. Yes, the odd coffee or lunch straight after a class but not even to the point of swapping phone numbers, and people usually tend to rush straight off. And I am a sociable and gregarious person living in an area with loads of baby activities. The reason that you don’t end up just hanging out with Mum mates all the time is simple- the babies get in the way
. They are all on slightly different routines so choosing meet up times is hard, one will always be sick/grouchy and need to be taken home or never make the meet up in the first place, or it is nap time, or someone has a clinic appointment or some other baby (or older sibling) logistical commitment and then as they get older and start to crawl you can’t have a flowing conversation as they need to be supervised too closely. On the other hand I absolutely loved just pottering about, me and DS, doing our own thing on our own timetable at home or the shops or in classes and more of the same with DH all three of us at weekends. For me having a baby was a time to contract my social circle, not expand it. The baby was much more interesting than I expected and kept me much more amused than chatting over coffee with women I barely knew. However I did (still do) have a very lovely and supportive private Facebook Group that was great for advice and sharing experiences and photos and funny stories. I also found that having DS brought me much closer to my in-laws and I grew to enjoy spending time with them much more than I did before I had a child.
All these comments apply equally to your concern about your DH not making parent friends on maternity leave- I don’t think it happens as often as you think and don’t think that it really matters.
Anyway, hopefully some food for thought. Good luck!