Where Will Everyone Sit?
Seating charts for large events are difficult, but can be helpful if you want certain people to be separated. Seating arrangements for more intimate gatherings may be even more difficult, as there is less space to put between people. For larger events, there is rarely a seat of honor that cannot somehow be paralleled. If your partner would like to sit at the table next to the head table at the wedding, it is probably possible to have a table for the other biological parent on the other side of the head table. This way you will maintain some equality in seating. This should be done with grandparents and other relatives as well. If possible, it may help to have both parents look over the seating chart if they are not the ones putting it together. For larger events, you may be able to split the room in half and give half to each parent. Each parent can then decide where to seat members of his or her family.
Seating people next to at least one person they know can decrease anxiety and make for a more pleasant experience for guests. Also, keep in mind any health conditions or other issues that guests may have. For example, a pregnant guest may be more comfortable close to a restroom or exit, while an older guest may prefer to be further away from the stereo equipment.
For more intimate events, seating may be more of a struggle. If there is only one place for a head of the table, there may be some feathers ruffled if one parent believes she should have that seat and another nabs it. Avoiding a head of the table may be necessary and can be done by using circular tables, or placing a child or a random person in the seat that looks like the head of the table seat. It may be easier in some instances to assign seating, and easier in others to let people choose for themselves. Assigned seating can help avoid awkward moments of, “Where should I sit?” But it can also provoke such responses as, “Why is my seat here? His stepmother must have done this to punish me.” On the other hand, not assigning seats opens up the possibility of arguing over a seat or ending up next to someone you don't want to be near. If it is decided that seats will be assigned, try to think of equality in seating, and move yourself to the back burner if possible.
You may want your stepchild to decide the seating arrangement and then go over it with your partner. If your stepchild would like you to sit next to her and her mother to sit all the way at the end of the table because they are not getting along right now, consider her mother's feelings. You can tell your stepdaughter that you are flattered that she would like to sit next to you, but feel that it may hurt her mother's feelings. You can plan a night for the two of you where you sit next to one another and leave the event seating one where her biological parents have preferential seating. Try to avoid physically taking the place of one of the biological parents. Seating symbolizes so much, and how we habitually situate ourselves tells a great deal about our relationships with one another. This is probably not the effect you want to achieve. For your purposes, try to avoid creating any seating charts that will cause discomfort and place people where they feel welcome and at ease.

