Society thinks worse of people who split when DC are really small.
But children are more screwed up by parents splitting the older they are.
We can't face the stigma of 'failure' so hang on and try and try.
In my case, things didn't get better, they have got steadily worse. It's awful now.
But DC would be really messed up if split now, I so wish I had done it sooner. Feel I have to stay and there are practical issues as well. I'm just not brave enough to get out.
Younger they are, the more adaptable DC are, 2 is so young it would become normal for her very quickly.
No, it's not healthy, but you are not arguing, so DD not in the middle of a traumatic situation. But, this is the role of love/relationships she will see. If there is no love, intimacy, it will affect her.
How does DP feel? Would you be civil and work things out in DD's interests, or would it be a car crash if you split?
Having a 2yo is hard work, do you want to work on your relationship, spend time together not being parents, try to rediscover some love?
If not, there are three possibilities.
You leave.
You stay to 'do the right thing' but your heart's not in it, it will decline, you will get more miserable, it will be harder to leave. You might even have another child to make things even more complicated.
You will meet someone else (or DP will) you will have an affair because you want some love, intimacy, happiness. Then you will leave anyway and it will be a mess.