I thought my OH and i had a terrible relationship until i stopped drinking. I wasn't an alcoholic - weekend drinker only, could take it or leave it if i didn't go out - just a crap drunk. I'd become overemotional, needy, depressed, and lash out at my partner who - also being drunk - would be an absolute cock to me as well as he didn't understand why I was being such a dick - basically that i was insecure and unhappy and needed him to 'prove' he loved me. After one particularly bad night when he called the police on me as he thought I would hurt myself (they came round to check on us the following Tuesday, very useful 
), I gave up booze for a bit bar a single glass with dinner if we had guests, and did some work on myself. We still occasionally quarrel, but much less, and at least now i retain clarity and perspective and can stop it escalating ridiculously out of proportion because i have emotional continence (except just these last months with our new baby, when the hormones and tiredness appear to be having the same effect as10 G&Ts!!)
On reflection we aren't hugely compatible in some ways, and in some ways never will be - but for me, our 'roots have grown around each other' and i couldn't be without him - half my brain is made up of running jokes we have together, memories of us, he's the father of my baby. Not but what I don't still get livid with him when he allows perfectly predictable traffic to drive him into a rage (for example), but i value him so much and would hate to lose his interesting, clever, funny, quietly thoughtful presence in my life.
Definitely agree that charitably assuming the best motives of your OH is a must - don't let paranoia make you assume they're 'trying to upset you', try and see their POV.
Another thing I've learnt is not to expect them to love you the way you love them - expect them to love you as much, but expect it to manifest differently, and watch out for the signs of love particular to them rather than assuming they don't love you because they don't do/say x. My OH is not very verbally expressive, but if i have a busy day lined up i will find all my bits and bobs are magically where i need them to be, neglected cups of tea follow me round the house when i don't have time to remember them, he buys the most incredibly thoughtful birthday and Christmas presents. This is his version of me showering him with compliments, kisses and I love yous, and as long as i remember to recognise that, I feel incredibly loved.