"Is there a perfect marriage" is a very childlike question. People are imperfect. Fairytales are for young children. It's the sort of question we ask when the real world is a bit much and we want to retreat to the certainties of childhood.
There are good marriages, string marriages, loving marriages, but no perfect ones.
I have been with DP since our teens, so around 40 years. We've changed beyond recognition from the kids were were.
We've been through some truly awful stuff with mental illness, nearly losing a child, depression, children with additional needs failed by both education and health systems, redundancy, addiction and bereavement.
We also have loving families, wonderful kids we've raised to adulthood, a happy home, interesting jobs, great friends, a lot of fun and a deep and loving relationship with one another. Because we worked at it. We saw other couples growing apart and decided we needed to invest time and focus on ourselves as a couple as well as all the pressures of family life.
Sometimes that was very hard to fit in. Sometimes I'd have loved to get on a train and vanish. But we didn't, we just kept talking, kept spending time together away from the children, and thrashed out arguments until we found a solution.
One of the sad side effects of the ease of divorce (which is a good thing, God knows we don't want to return to a past where women were trapped in abusive marriages!) is that the idea that a happy marriage is hard work has been forgotten.
If you seriously want to be with one person for 50 years, you need to acknowledge that both of you will change a lot over that time. You need to be sure you're changing in complementary directions rather than drifting apart. That you still know each other well rather than assuming you do. And that you still have a bloody good time together.
That's only possible if other partners are committed to it.
In your situation, OP, I have nothing but sympathy. Couples counselling can be great - it can clarify that there's something worth saving or it can show you you'll be better off apart. Whichever route you choose, I wish you the best.