Well, yes relationships require effort to work, but it shouldn't be hard work, all the time. There should be plenty of times where you're happy and enjoying yourself, and if you're worried about how your partner is feeling, I reckon it should be a genuine concern for their happiness and wellbeing, rather than because there will be repercussions otherwise, you know?
May the universe strike me down for saying this, but I don't really believe in soul mates. Or at least, I don't believe that it's necessarily your partner who is your soul mate. I have several people in my life and who've come and gone with whom I connect/ed on an incredibly deep level, and they're not M. I'm not saying I don't love him, he's my best friend, and we enjoy each other's company, and there's still a mutual attraction there, and we parent well together and I can see us growing old together... it's just 'soul mate' isn't how I'd describe our relationship.
It sounds like it's rough for you right now :hug: I hope things improve for you soon.