I think they were truly in love and remained so in the intervening years but they were such different people that it felt inevitable that they weren't going to stay together forever, especially with their son turning to the dark side, another inevitability. I anticipate that Han's death will continue to be a big blow for Leia moving forward even if they had grown apart. Because of what it means for her son and because Han was so important to her. I think she may be more blood thirsty in the next movie.
I'm really curious to see what Luke's reaction to it is. He might already know due to some indication through the force. If not Rey is going to have to explain why Han isn't piloting the Falcon.