Ladies,why is is never enough?

The past relationships I have had all started off well, with respect and understanding. Over time the ladies seem fustrated as they always want more. More time, more involvement, more attention.. this puts huge pressure on me and is not a comfortable thing to endure in a relationship.

I am comfortable in life, have my own house, dog, kids (one week on, one off) and friends and family, a job that allows a comfortable lifestyle, a really nice situation I worked very hard to reach. These past ladies were all single, I have kids and I suspect this is the crux of the issue. There is only so much free time I have and will not give up time with my kids for someone I have dated for less than a year. I am also not rushed to introduce the lady to my kids or family, I feel the relationship has to be stable between us first. This takes time. After +- a year seems about right to me depending. I wouldn't want to meet their kids before that either.

As time goes by the ladies want more of me and my family, to be more integrated into my life. I get this, but this should come as a natural progression, not be forced or rushed. Forcing the issue only pushes me away. This despite numerous conversations about it all, they say one thing but a act differently.

I have never made any such demands on them or their time. It's about communication and listening...

Am I in the wrong here? I feel I should only date ladies with kids as they would have a better understanding of the time needed to bring up kids, and not be angry when I don't have time for them because I am with my kids.

A ladies perspective would be nice. Thanks and have a great weekend.