1. He's not against marriage in general so much as himself getting married. Marriage is a commitment he doesn't feel he's ready for. It's easy enough to say you're going to date a person for the foreseeable future, but actually living with them and committing to spending your life with them is harder. Plus he knows he's hard to be with and it's less messy to have his girlfriend leave him than a wife. It's not something he wants to rush.
Also, the fact that children are likely to come after marriage scares him. Unlike Erik, he's in no hurry to start a family.
2. Not at the wedding, no. There's an extra scene available from the extras menu if you've seen a specific late game scene with him though. It shows him slowly starting to get over his reluctance to commit.