I'm a single mum and can honestly say it is FAR easier being a single parent than it is parenting with an unsupportive partner. ExH1 left when DS1 was approaching 2, and DD was 4.5 months. He completely left our lives so the children have had no parental input from him. We have tried to find him, but he basically chose to opt out of parenthood.
ExH2 left when I was around 17 weeks pregnant with DS2 who is now 20 months old. So I did most of the pregnancy alone as well. I didn't have an easy pregnancy at all, with severe hyperemesis to term resulting in many hospital admissions. And we managed fine (largely thanks to the amazing support here on MN).
I actually love that I am raising my children as a single mum now. It wasn't what I expected, but the freedom to make my own parenting choices, the lack of any arguing or tension - it's bloody brilliant. We are all really happy, and DS1, despite this "lack of a father" which according to studies can have a very negative impact on education etc, just became one of only 3 from his primary school to pass to our Grammar. I am so proud of him.
Financially I am able to do this - I have a well paid job, rent a couple of rooms out (my house, although still needing work is pretty huge). Practically I juggle nursery with support of an au pair (for the elder two after school and some housework) and a couple of days a week my youngest is with his grandmothers. All managed with only a very small monthly maintenance contribution from the father of DS2 (less than 25% of the childcare costs I pay for him).
I am also expecting DC4 - completely unplanned, contraceptive failure. And STUPIDLY the father is ExH2. But he's said he will have nothing to do with this child, will not be named on birth certificate etc. (and finally I can lay the demons of that awful relationship to rest) So, in a few months I will be a single mum to 4.
Like I said, practically and financially I can manage this (with absolutely no government support). There are days when it feels a bit much, but a cup of tea seems to sort me out. If, from a practical perspective, you feel you have the resources (financial, support network, time) then I wish you all the best. There are huge advantages to being a single parent, and I wouldn't have it any other way.