I'd just go and get married the two of you. It's not about the children, or anyone else! It's about the two of you!
I disagree. I get that different things work for different people and only you know what makes you feel comfortable... but for us, when planning our wedding the thought never occurred to exclude the kids from the day. We took the view that the by getting married and creating a blended family, then that decision affected everyone, kids included, so the kids should be part of the day. Yes it increased the costs because the girls were my bridesmaids and the boys groomsmen BUT the long term benefits far outweighed the fleeting pain caused by the additional cost.
For us, the blending of our family meant that we recognised that life was never going to be the same again for anyone, kids included, and that was bound to cause plenty of bumps along the road as time went on without starting off that way. We wanted to create a day that was meaningful and joyful for everyone, and that created good memories for everyone. Every family needs a "bank" of good memories and shared experiences they can draw on when things get rough, blended families even more so because they face challenges that traditional nuclear families don't.
In a blended family you have to create new routines, new living arrangements, new memories, new traditions. It's a constant readjusting and balancing act that can be rough for everyone. Stuff blindsides you when you least expect it and unless you build a strong foundation from the start, the whole thing gets very rocky very quickly. Having blended our own family nearly 10 years ago, I can honestly say I can see why so many blended families fail!
I know that's probably the last thing you want to hear when planning a wedding, but trust me, we tend to start as we mean to go on, so yes, it's your wedding and it IS about the two of you, but it's also about the family you are creating simply by getting married.
Whatever you decide to do, have a beautiful, joy filled day 