My wife (33f) takes our children to her first husband’s grave every year, and I (34m) don’t know how to feel about

My wife was married before me to her high school boyfriend, but he died in a car accident when they were 23. I met her a year later, and we started dating within a few months. We got married when we were 26, and now we have two children, one aged 2 and the other 4.

She has the habit of visiting her first husband's grave on the anniversary of his death, January 6, every year with our kids. She also places flowers and lights candles at the grave. I have never gone with them because she has rejected the idea in the past, and I feel she doesn't seem to want my company there.

I don't know how to feel about this. On one hand, I understand that she still misses him and that he was an important part of her life. I don't want her to forget him or feel guilty about being happy with me. On the other hand, I feel excluded. I wonder if she still loves me as much as she loved him, or if she sees me as a substitute. I worry about the impact this might have on our children, whether they might become confused or something similar.

I have tried talking to her about this, but she simply tries to avoid the subject. I love her and want to support her, but I also want to feel secure and respected in our marriage. Should I insist on going with them and try to be part of this ritual? Should I ask her to stop taking our children to her first husband's grave? How can I handle this situation?