I agree with Christa.
It seems like Erik always has an excuse for why something won't work. Are you certain that he's 100% invested getting married? I hate to be the one to say it, but it seems like he's been putting up roadblocks the whole way. I would hate to see you get hurt in this situation.
I am just speaking from my experience, but I know that my husband and I went through a lot, including calling it off once, before we finally made the decision to go through with it and do it in Cabo. And once we did, he was there for every major decision, even if only in support, but often times he was making the decisions with me. Because it was important to him that the day reflected him, and US through his eyes. (does that make sense??)
Beyond that, this is a really important and challenging period in your relationship and it also really is going to set boundaries for the future of your relationship with your MIL. If he isn't willing to go to bat for you now that's a major red flag in my book. It implies that either he's not willing to make your feelings a priority, or perhaps he just doesn't care enough to deal with it. Either way, it seems like now would be a GREAT time to sit down and have a serious talk with him about your future. And I would not bring up the wedding, rather I would focus on talking about your future plans and what the two of you really want from your relationship. If you find that you have mutual goals and then maybe there's something else that's holding him back. Perhaps it's the fear of committing for the rest of your life - I know that was a HUGE fear of mine.
I know that weddings are supposed to be the happiest day of your life, blah, blah. But what truly matters is the commitment that you make.
Not the hooplah. A million dollar blowout wedding isn't going to make things any better, or make you two any happier if you're not 100% sure.
I think I am rambling now, and I don't want to come off as bitchy, I just feel a bit skeptical. I've watched you jump into planning and projects since you have been on this board, and I don't think I've heard you say that your FH has been on board for any of it. I really do wish the best for you so of course, take my advice with a grain of salt. These are just my outsider observations.