Clearheaded, I don’t think everyone needs to be in love to make their marriage work. I needed it though. I also recognize that loveless marriages can be hard to live in.
I think selfishness in marriage is also really hard. I know because I am naturally a selfish person. It has taken a lot of work on my part to become a better spouse. My husband is naturally amazing at it. I’ve learnt a lot.
Both spouses should constantly be trying to anticipate the needs of the other spouse in an effort to improve their marriage. The more you give to someone (assuming its reciprocated in some way), the better the marriage. I’m not talking about “stuff” (like jewelry or cars), I’m talking about the entire picture.