I'm a divorced co-parent of an 8 year-old girl. I never call myself a "single mom" because her dad is totally involved in her life. Some of my friends call themselves "single moms" and their exes have the kids up to 1/2 the time!
I don't have one regret in divorcing my ex, but it took me many years to come to that decision. He suffered from depression (since diagnosed as bipolar) and drug use, and repeated unemployment. Since our divorce he has gotten better medical help and is now on full disability (for both mental and physical disabilities) and he is more together, and a much more involved father than when I was there taking care of everything.
My life is better because I have the energy to pursue school, work, friendships, and all the things that were so hard when I was using all my energy to just keep things together and support the whole family.
If you split up, I recommend a mediator, not lawyers. It is up to you and him how you parent your children the best way possible, not lawyers or the court.