I used to be friends with a girl I met at work. We really clicked in the beginning, and became friends. She invited me to stand up in her wedding, and I was very happy for her when she got married.
At the time I was single and dating (and meeting only jerks) and she was really supportive. She'd listen to my dating stories and tell me I'd find the right one eventually. And I did. Just a few months after she got married, I met a great guy and fell in love. We decided not to wait, and got married pretty quickly. I asked her to stand up in my wedding (as I had done for her) and she agreed, but things were different between us. She would make these snarky comments once in a while about me and my husband.
The four of us (her husband and mine and me and my friend) would often go out and have fun most of the time, but then she'd still make those comments here and there. It was all subtle, but still, I noticed. I never said anything though. Looking bad I guess I just chalked it up to her being in a bad mood.
Eventually she had kids and started saying she was too busy to get together. I understood, but tried to keep in touch with email at least, and she wouldn't respond. But when she wanted me to do something (come to her baby showers, give her a recipe) she'd find the time to email or call. It seemed like she only wanted to contact me when she wanted something, and even then, her little comments would still come out.
It seemed like I was the one keeping the friendship going, so eventually I just stopped trying. I didn't email or call. Our friendship just sort of fell off.
Recently I bumped into her and once again, she was very cold toward me. It had been years since we'd seen each other, and she asked me basic questions about my life (where are you working, do you still talk to so-and-so) but even then she seemed snarky. In fact, she didn't even seem like she wanted to say hello, but felt obligated because we'd bumped into each other.
Seeing her again made me realize how much I didn't miss her. She gave me the impression that the minute she left, she'd be talking about me and being her typical rude self. I walked away from her glad that we'd parted ways.
But then today I received an email from her, saying that it was nice to see me and we should have lunch and catch up. I'm confused. Her demeanor led me to believe she was her regular snarky self, but was I reading the situation wrong? Does she still want to be my friend?
Just because she asked you to lunch doesn't necessarily mean that she's going to be a good friend suddenly. It could just mean that she wants to find out more about what's been happening with you the last several years, or that she wants to talk about herself.
You mentioned that she acted "snarky" when you saw her, and that tells me that she has not changed, which means there is no reason to believe your friendship (if indeed she wants to be friends again) would be any different. If she had changed, she would have been happy to see you and sincere in her comments.
When Friendships Change
Friendships do change when people have children, but you mention that she was already starting to act rude to you before that. She was a good friend to you when you were struggling, but when you met your husband, her attitude changed. You've been trying to figure out what changed in her ever since.
Some people can only act like friends when they feel superior to another person. Since she was happy with her husband, she was able to extend friendship to you because on some level she might have felt sorry for you. However, when you were happy, she could not longer relate. She might have even been jealous.
Subtle Changes That Affect Friendship
It's difficult to understand why some friends seem to change toward us, especially when the change is subtle. When there is a big argument, you can at least talk things through. But when there is simply a small but negative change in someone, you might not want to bring it up. It's only years later, as you noted, that you realize how unpleasant the person was and how glad you were to move on from them.
Ending any type of friendship is sad, but you tried to keep things going in the past and she didn't respond. Now, you've bumped into her and were left with a bad impression. You need to trust your gut here, and can do one of two things. You could meet her for lunch and see if she has changed, or simply ignore her request. Either way, remember that you deserve someone who is willing to treat you kindly and be happy for you when things go well in life. Friends need to be there during the happy and sad times.