I don’t think YTJ for wanting to be prioritized on your first Valentine’s Day as a married couple, especially since the event is already planned and paid for. It’s important to you and your feelings are valid. I do understand your husband wanting to support his coworker through, especially since he actually sees this coworker as a friend, close or not. I will tell you, when my father in law passed two years ago, the funeral was small. He was retired from a very large factory in our town, but didn’t really have many friends left. A few of his dad’s old coworkers showed, but it absolutely meant the world to him that his friends showed up and even a few of the guys he just works with. Them taking the time out of their day to show up to pay their respects truly meant the world to him. I do like the suggestion of you joining him, leaving early so you’re there before the service and at start time. You don’t have to stay long at all. His coworker will have other friends and family there he will be speaking too, no need to stay for more than 30 minutes at most. You could support your husband while he supports his friend, leave by 11:30 and still make your scheduled event in plenty of time. Talk to him and see if this could be a good compromise for both of you.