"I have a wonderful, child-loving Mother-in-law. She loves taking care of my 18 mo. old son and often volunteers to take him on weekends. As a parent, I'm thrilled (duh!) to have some free time with my husband or just some extra wine and sleep. The problem is how much is too much of a good thing?? I'm sure it's a reflection of my own insecurity but I'm afraid that my son will think grandma is more fun and will want to be with her more than us. I know that time will come when he will definitely prefer gramma to his own parents simply because she'll let him get away with more. But, it broke my heart one day to hear him say "Mama" to my MIL.
It's not that he stays at Gramma's every weekend all weekend but probably every other for either one night or two. I absolutely want my son to have a wonderful relationship with a Grandmother that loves him but how do I do that without feeling guilty that I'm handing him off or that he'll prefer her to us? I guess that other side to the equation is my own parents. They live further away from us than my MIL so they obviously don't see my son as often. I'm so worried that my MIL is going to be become the preferred grandparent and my own parents will be the outsiders. However, the geography is a valid hurdle and it's just not possible to see them all the time.
Wait, I'm not done yet :-) there's more. I also have a nephew (my sister's son) that lives very close to my parents. My folks see him all the time and he recognizes them and loves seeing them. They seem to lavish so much attention on him and I feel like my son gets the shaft. Again, the travelling is the issue. Maybe this is all very normal and I just don't know how to deal with the guilt and worry on all issues. How do I deal with "super grandma" on the one side and "absentees-thru-no-fault-of-their-own grandparents" on the other side? I know that if the roles were reversed and my parents were super-close prandparents getting my son on the weekend and my MIL was absent I probably wouldn't feel so twisted-up about it...."
Release the guilt. You're in a mostly great situation, and once you start accepting that it's normal and healthy you'll be able to relax and enjoy it more.
It's wonderful for your son that he gets to spend so much time with his grandma, who sounds just thrilled to be so involved with him. It sounds like the ideal situation, really, to have someone you love and trust who can take him enough to give you and your husband a break. You're probably better parents because you have someone to share the load. It's so much closer to the way humans are designed biologically to parent--in groups, not just lone families marooned in their own houses trying to hold it all together by themselves.
Actually, I take it back. It's not the ideal situation. The ideal situation would be if your parents also lived close to you so your son could spend a bunch of time with your MIL and a bunch of time with them, too. I think you've correctly identified that a lot of your misgivings about your son spending so much time with your MIL stems from the fact that you're sad he can't spend as much time with your parents, and jealous that your sister's son gets the attention your son can't have because of distance. I'd say that you should think about how important it is for your mental health for your son to see your parents, and what form those visits should take.
As an example, we lived in the same town as my dad's parents and 12 hours by car away from my mom's parents. She and my dad decided that there was no way we could see my mom's parents often, but we could see them for long enough visits that we got to know them that way. So every summer we'd spend at least two weeks with them at their house, and we'd try to go once during the school year for at least a week, too. I'm trying to do the same thing now with my kids (we live close to my ILs but 600 miles away from my family). There are things we can't do because we prioritize visits to my family above other things we could spend money on. I sometimes feel like a pauper (especially compared to other families we know in NYC), but my sons know my parents as well as they can at this age.
So maybe instead of focusing on what your son isn't getting because he doesn't get to spend every weekend with your parents, you could think in terms of trying to give him one or two long visits with them in which you go to them or they come to you. Your sister's son is still going to be the Everyday Grandson, just as your son is the Everyday Grandson for your MIL. Speaking from experience, that's not such a bad thing. We got spoiled by one set of grandparents, and my cousins got spoiled by my mom's parents. It kinds of balances out, and I didn't feel any less love from my mom's parents. And I knew both sets pretty intimately, because I saw one set all the time at home, but I'd spend intense time with the other set (14 days in a row) at regular intervals.
I'm sorry he called your MIL "mama"! That must have been brutal. But he absolutely knows who you are and who she is. If he hadn't called her "Mama" that day he probably would have said it about the dog--18-month-olds are testing limits all the time, including limits of language. THis, in my opinion, is probably going to be the biggest challenge you're going to face in the next two years of having him spend so much time with your MIL, since she'll have different rules and expectations than you do. But your son is smart, adn he'll test you all but you'll figure it out. And it will be so valuable to him to have a grandmother he knows so intimately in his life.
So please don't feel bad about it. Make your plan to get him more time with your parents, and then go have a glass of wine with your husband while your MIL is sitting through another round of Dora.