I will give you the benefit of the doubt and assume you didn't meant to be goady.
Actually, it's very difficult, and my DD was a teen when Ex and I separated, so we were past the difficult baby/toddler/small child stage. She was old enough to make her own way to and from school at that point, so I didn't have to consider dropping her off at childcare or school, and picking her up again. I only have one child so I appreciate that's considerably easier than two, three or four children.
But it's still really difficult. There are financial considerations. Ex seems to be very rare in that he pays a decent amount of child maintenance. But my mortgage and all of my bills have to come out of one salary. I am paying a lump sum to Ex, in exchange for him transferring his share of our home to me. So I also have loan repayments to make each month. Right now, I'm also saving for university fees (I'm in Ireland and student loans are less common here).
The separation was very tough on my DD. She has had to adjust to her parents living in separate homes and seeing them at separate times. Family times like Christmas/New Year's/Easter/her birthday are carved up into Mam time and Dad time. It's easy to say that you get one day of rest (without the children) at weekends, but what if that day is Christmas Day or Easter Sunday or your birthday?
DD's Dad has a new partner and the partner has DC of her own. So DD has had to adjust to a ready made family - one she didn't choose. She has the hassle of packing bags when going to her Dad's house and re-packing them to come home. There's the inconvenience and stress when she's missing something because she left it at her Dad's house (or vice versa).
I'm glad that my Ex chose to stay in DD's life and maintain his relationship with her. But DD is a lot closer to me and if she's upset or having meltdowns about something, she saves them for me. There were a few of those in the immediate aftermath of the separation and a few more further down the line (years later), as DD reached adulthood and started to process it all. Please don't under-estimate the emotional toll of separation and divorce on children. I have arranged and paid for counselling sessions for DD, to help with this. I've had a lot of stress and worry and guilt about the impact of the separation on DD - not just now, but how it will impact her in the future.
There are practical considerations too. Everything to do with the house and garden falls to me. All housework, all gardening, all maintenance, all purchasing decisions. If I have to get a workman in to do a job, I have to take the time off work to let them in and liaise with them. There's nobody to share any of this with.
Loneliness can be difficult to contend with. Loneliness in the sense of not having a partner/husband. And loneliness when DD is with her Dad. Sometimes it feels like the world is full of happy families. I could, of course, consider dating. But what impact would that have on DD? How would she feel if I moved another man into her home?