I did not manage to find my wife until I was in my late 30s. I had to date a lot of women from my teen years to late 30s trying to find the right lady.
To my knowledge none of the women I dated were unmarried mothers. Most of them had a civil or decent even a good relationship with their ex husbands, and I met a few ex-husbands. It is rare to find a woman over age 25 that has not had kids.
Many of the ladies I dated were just looking for a break in the routine of being a mom, and dated me on the nights their ex-husbands had the kids. That was great for me.
One of my good buddies is in his 50s now and single after two marriages. He has a daughter that is an adult. At that age most women he dates have adult kids. He loves to go cougar hunting on Saturday nights. Catch and release program. I am so glad to be married for 27 years, and not out looking.