We've been married thirty-one years - as I said to DH, people get less for murder.
We are the proverbial chalk and cheese. DH is very sporty; when he is not sailing, diving or surfing he's dashing lycra-clad about the countryside on his bike. I, on the other hand, am bookish and reflective. There are things we do together - walking in the hills, restaurants, sometimes theatre and cinema - but never really spend enough time in each other's company to become bored.
Really, despite having an emotional closeness and loyalty borne of our intertwined history, we're the opposite of soul-mates, but paradoxically I think this type of relationship can facilitate a long marriage.
The IL issue sounds infuriating. I had a poisonous MIL - Evil Yvonne I used to call her (not to her face!) - but DH couldn't stand her either, so she didn't come between us. But I think in your position I would say to myself, "Right, Storm, you've let this upset you long enough. Your DH and his beloved Ma are not going to change their attitudes now, so you change yours. From now on you're going to be impervious. Let them get on with the mutual appreciation society and have a secret laugh at them!".
Easier said than done, I know 