And I am one myself.
I had DS1 at 20 - I did date and subsequently married DS2's Dad and gained a wonderful DSD who is still with me.
I split up with DS2's Dad and kept all 3 kids.
Since then I have worked, looked after the kids, messed about with the dog, tried to keep the house and garden OK-ish.
I don't think the kids would appreciate a new face around. I do not know how I could incorporate it into our lives.
I worry about kids who have "Mum's boyfriend" around the house - without a CRB check, who is in your house with your kids?