If this is a deal breaker for her, then you have to accept it and move on.

While I think it's wrong for her to try and force you to love her kids as your own, it's also wrong to force her to stay in a relationship with a man who can't do that.

As a mother, there's no way I would raise my children in a home where they aren't loved by both adults. I also would not be able to live with a man and his kids if I didn't love his kids. No matter which side of the fence I ended up on, I could not stay in a relationship like this.

Do you have any nieces or nephews? Try to hold off on having an argument about it for now, but when the next school break rolls around, take on the niece or nephew for the whole time.

But don't actually do anything with him/her. Just bring him/her home, and tell DW, "He's ours for the whole week - isn't that great!" and then go out with your friends.

If she complains, ask her to love him like her own. And make it last the entire week - no breaks.

I think this might sound ridiculous, (because it is) but sometimes it's really useful to SHOW people how they are acting. They need to be confronted with their own insanity before they realize how nuts they are being.

See that tv show Crash Test Mommy - what they did wrong was always put 'extra' on the husband/friend's plate. They should have just left it normal.... that was enough.

Is your GF's kids Bio Dad in the picture. if not she could be like many "single" moms out there desprit for a dad in her kids life. it is alot to ask of you or anyone in our situation. I have a lot of single mom friends that i have to remind them of things like this when they start dating a new guy.

Do you have any positive feelings for the child? If you do try to focus on those and let your SO know that you do care about them and their welfare. You want them to be healthy and happy and you are willing to work with her towards that in whatever way you feel comfortable (being involved with the step kids or by supporting your GF but disengaged from the kids or whatever works for you). If you can focus on the positives hopefully that will help.

I love my SD, I care about her and I worry about her. I think I am lucky though as at 6 SD is very generous with her love and is a sweet kid. But I don't love her like her parents do. Some of that is forced by the circumstances, I have to keep distant otherwise the way that the two of them screw up her life would drive me crazy. Some of it is just that she isn't mine, and I have been in her life a relatively short time. When she cries I can see how upset it makes my husband, but it just doesn't affect me emotionally at all. When my husband can't say no to BM for us to have SD for extra time, for him it is him getting to see his daughter extra, for me it is BM screwing up our plans again.

If the "loving them as your own" is a sore point with your girlfriend, sometimes it is easier just to let it slide than to bring it up again yourself. Just show her the ways that you do care. If you can focus on the positive relationship you've already developed with your step-kids, let her know that love takes time and effort on both parts to grow but that it is unlikely that you will ever feel the same about step kids as you do your own kid. Does she also expect the kids to love you as much as they love their Dad? But with that you also need to show her how you will try to make all of the kids feel valued in your home and make them all feel equal, no matter how you feel towards them.