I think what you're experiencing, OP, is the misogyny that blames women for everything.
I was looked down by some people for being a single parent (first child's father left me at 8 months pregnant having got another woman pregnant). Second child's father had an affair and was somewhat abusive (financially and emotionally).
Some people then had an opinion on me being a single parent for nearly 10 years.
Then people had an opinion on me dating again.
(In many cases, it was the same people every time).
Now, I'm older, my children are adults, my partner is older and his childen are adults so I don't get the blended family issues. But there were some comments when I got together with my second child's father. We were together for 12 years and there is an 8 year age difference. He was a great stepdad, and the issues ony really arose when our shared child was born.
I was also criticised for, let me see, going to university when I had a child; working/having a career when I had a child (given i was a single parent, i had no choice and suspect I couldn't have won either way on this one!); for breastfeeding; for using a childminder rather than a nursery/raising the child myself; for cooking from scratch and not feeding my childen chicken nuggets and fish fingers. The list goes on...
What I realised early on is that, whatever choice you make, there will be someone who feels you need putting straight for it so, as long as you are satisfied that you are doing OK, that's all you need to worry about.