Hi Kate. I'm a long way off from having to deal with this myself (kids are now 12 & 14) but I'll relate some ideas I've seen/heard others use...
A friend whose father died had a special ceremony at the rehearsal supper during which they lit a large candle for her father, then smaller ones for other family and friends who could not be there on their special day.
Another couple I knew had a stand at the church, and a large photo of the grooms mother on it - both bride and groom went over and kissed the picture before the ceremony started as a way of silently acknowledging her presence in spirit.
Yes it's sad their father cannot be there in person, but there may be a way, a symbol, picture, item of clothing, that they can use to represent his presence. Hope this helps.

Kate, my stepson graduated from law school in December. It was hard but not quite as much as I had anticipated. My stepson had asked me to find a picture of him and his Dad from a previous graduation and that was a great idea. I think any photo of the two of them being happy together would have worked well.
Neither my stepson nor my stepdaughter are yet married, so I may have that to come. I am sad that my husband never got to meet my stepson's girlfriend and know that my MIL is sad I never met my FIL.

It is painful to think of these events. I have talked with my daughter about things of this nature and we have worked together to find ways to include him. She has decided who will fill in when she walks down the aisle and we have talked of having photos there of him. Working together on a solution that would help heal the emotional side of it has been really nice and we have drawn closer by doing it.

I went to my niece's wedding 1 1/2 years later, it was hard to control the tears without my husband by my side. I could imagine how difficult it would be for you. On the other hand it could also be a happy event to help you move forward. I say this is because I experienced the arrival of our brand new grandson, who has brought us out of depression and gave joy to the whole family.

I hope the wedding will bring you much joy. Your husband will be there watching over you and your family. Hugs to you.

Our son graduated College and had his ceremony 6 months after his dad passed. We made it through and in lieu of my husband , my sister was along for the ride (she would have come regardless being his godmother) yes there was some occasion for sadness but then the sense that despite what happened, our son made his father proud by carrying on and finishing his schooling, accepting a job in his field and doing what should be on his journey through life. In dealing with these occasions we speak of it frankly and get a lot of the negative emotions out prior. DD and I often talk of the day that she may have to walk down the aisle without her father and she tells me that her plans was always to have both her parents walk her down so now when that day comes she will have me filed the spot intended for the two of us in the same manner that I have had to do for these last two years. She added that I was doing a find job of showing her how to be strong. The anticipation is often worst then the day. A marriage is naturally an occasion for joy and I truly believe that joy will shelter the sadness and carry it in a special way.

My daughter was engaged when Jim died. He knew of her plans. At the wedding they had a tribute to Jim. She wanted to cancel her plans as it was just 3 months after he died but I told her no Jim would want her to go on with the wedding. It was hard for me but I felt as if he was there by my side. I really think our family needed some happiness after all the sadness we had been through. It was just as Jim would have wanted.