I also am a stepparent, dated 2 years, married 30, and helped raised my stepson all that time - he was 14 when we married I think. Now we have 3 grandkids. I call it a spiritual adoption of both stepkids and the grandkids. We fit in exactly where we want to be so long as we are welcome. For me it was easy with the grandkids because they always knew me as grandpa. Regardless of titles, embrace the opportunity to be a part of both your daughter and her children's life. Just one more challenge we stepparents face -- but really, nothing should change when our spouse dies. God bless you ~ Scott

your step daughter obviously feels deep attachment to you. Cherish that love, and being a continuing part of their lives.
I understand it is hard always feeling like "the sad one" at gatherings.
However, it is better than being treated as if you do not belong "where you thought you had before, and therefore always would".
Family are those who love & welcome you. All your years of caring for her are being recognized as being important, and you are family.
Sometimes in grief we feel that we fit NOWHERE. even closest blood family.

I think Scottie and AfterMom said it well. Being included is a compliment to how they feel about you. Losing your husband in 2011 isn't the end of grieving in 2015. You are still trying to find a way to live without him. I understand the sadness. Sharon

Thank you all who commented-- I had a nice text exchange with my step-daughter, telling her that I was sad about her dad not being around for his grandson and she shared her sadness as well. I feel much better knowing that she understands-- and that we understand each other! That is a powerful bond between us.

I enjoy each day as it comes. My stepdaughter was 11 when I married her father. She now has two children and is a widow herself. I love my grandchildren, but I know one day they'll be adults and not have time for me. That's why I live in the moment.

My stepdaughter was 25 when I married her dad, and it was hard for her to accept me into her life. She wasn't too happy when we had a baby, and over the years we were cordial to each other, but not that close. When my husband was ill with cancer, I made sure to keep my stepdaughter informed, and snuck away from my husband to call her frequently to let her know how he was doing. He was in denial about his decline and prognosis, so I had to speak with her privately in order to be honest and real. I called her when he took a sudden turn for the worse, and told her to get on the first plane out here. She arrived in time to see her dad for a few hours before he passed away, and during the next 10 days, as we grieved together and planned his memorial, my stepdaughter, my daughter, and I bonded and became very close. It's bittersweet that it took his death for us to appreciate each other, but we now are very close and feel very connected. I think keeping in touch with me and her sister helps her feel connected to her dad. I've heard so many stories of things getting weird with stepchildren after the parent dies, but if you can still be involved in their life it is a huge blessing. My step-grandchildren have grandparents, and in trying to figure out where I fit in, they chose to call me Bubbe, which is the Jewish name for Grandma. My relationship to them is not like a grandparent, but I still have a role in their lives.
I encourage you to go and enjoy that new little baby, continue to have a relationship with your step daughter, and don't worry about labeling it or defining the relationship. Just love each other!