A good parent puts their kids first. Sometimes.
Sure the kids will be at the core of their thinking, but sometimes our needs as people must come before our children's.
It is good for them to see a person putting themselves first, as it teaches them too to put themselves first sometimes.
If we put ourselves at the bottom of the heap all the time, how exactly do we expect anyone else to do any differently.
We can of course decide that relationships are not for us, but don't put that into the kids. That's why I said martyr. Because it's all a bit too "won't somebody think of the children???"
We need to model positive in as much as we can. We need to think and make the best decisions. Even if we completely ballsed it up choosing our dc dad, indeed Arpege 
Show our children how to get into and out of relationships, show our children boundaries and non-negotiables, respect for ourselves and others.
Yes there are others who are Hurt, damaged or who have behave and don't think so thoroughly, but they are in the minority.
I sincerely hope that this is a wind up thread because so much judgment and ignorance in one person is a truly hideous prospect.
I am pissing myself at the Op-approved method of dating. You have to meet them at work aft t a couple of years... Anything else is sordid and unsavoury #wtaf
Op, if you are real, you are in serious need of therapy. The thinking you display is warped and will not serve you or your children well.