how did u know (successful partnerships only plz <3)

when you can fart, sleep, and shower together all in good fun and feel comfortable doing so. from my experience you really "don't know" per se, it just comes naturally while intrinsically loving and showing compassion for him/her

as similarly said above

Things just work, you instinctively sacrifice a little of yourself to make your partner happier, without noticing it, and they return the favour.
you slowly start to live less for yourself, and more for your partner.

You have common interests, common hobbies, common beliefs, and most of all can be 100% yourself around them, you dont have to change yourself and how you act around them.

and most importantly i think they challenge you, in a good way. They make you better some how.

I think its happening with me
definitely pushing me to be a better person

I've been married for two years and with my wife for six years total.

The most important factor in a relationship is trust.

The way you know that you're with the right person, apart from mutual trust, is that you feel absolutely comfortable around them.

Common interests don't matter too much, but having similar personality types is good. For instance, my wife and I are both homebodies but have completely dissimilar tastes and different levels of appreciation for different media. I have to constantly pause and explain things to my wife while we watch stuff because I know jokes go over her head and she doesn't connect any of the dots.

Don't feel like you have to find a one of a kind partner. Just find someone that's sweet to you, cares about you, and is loyal to you. Everything else will shake itself out.

When you can poop with door open

I can vouch this. Exact same feeling

I’m almost 8 years in with two kids, married, and a pretty incredible life.
When ya know ya know.

Happy for you man

When you can talk and talk and talk and never get tired of it.