Help me! What answers can you provide for my question?

Maybe I'm being a bit negative, but I feel we're living in an era where almost nobody loves each other forever. It's the same story: couple fall in love, get married, then comes the kids & that where it goes downhill. It makes me believe even more that kids (& not having a ton of money) ruin marriages. Did my sister & me ruin our parents' marriage? Others who's marriages are still strong, congrats, but I feel a bit jealous & angry that there's lasted while my mom & aunts didn't.