Typically, it's the dad that does the spoiling because he gets a smaller amount of time with the kids, but sometimes it can be the mom. In either circumstance, it's important to understand what you can do to handle this situation properly.
When one parent spends more time buying gifts and trips for the kids, it can make it hard for you to compete. You may feel like you're the bad parent because the kids get excited about all the things he or she buys them. The awkward part is, you can't say anything bad because you know it's going to hurt everybody involved.
This is a very common situation and there's no easy way to handle it. It starts with the type of custody arrangement you have with your ex. Another part of it is the type of relationship your ex has with your children.
Sometimes one parent thinks they have to spoil the kids to establish a relationship with them. Since they don't get them every day of the week or most days, they are not involved in all the daily situations. This leads the parent to believe they need to spoil the kids in the little time they get with them.
One of the best things you can do if you're the parent on the other side of the spoiling is talk to your children about it. Explain to them that dad or mom is like the grandparents and wants to make the most of every minute he or she gets with the children. This means, when he or she gets time with the kids, he or she wants to make the most of it.
Explain that you cannot do that because there are too many day-to-day things and expenses that must be handled. Tell them it's okay and they can enjoy the best of both worlds.
In some circumstances, it can help to talk to the other parent, as well. Explaining how this appears to the children and the confusion they may experience can help.
Of course, you have to consider the intent behind the spoiling. If it's being used to make you angry or get under your skin, you may need to consider another approach.