Relationships can be tricky even at the best of times, but bringing MS into the equation can really take its toll. That’s not to say it’s impossible, but you really need to work hard at the relationship. I’ve been married just over 6 years, and it can be really hard - we really have to think about the meaning of the vows we took (better or worse, in sickness or health)! One of the things that my missus finds hard is that, in many ways, she has to choose to live a disabled life. For example, things like the fact that we can’t go to the beach or walking in the hills because I use a wheelchair.
But like I say, it’s not impossible, and you need to have clear, honest communication. And you also need to know you’ll both feel different things at different things at different times, and you’ll both need time to grieve the loss of your old life, and also grieve the possible loss of hopes & desires for the future (her wanting to have little arguments may well be part of that grieving process, for example getting angry - it’s not wrong, it’s perfectly normal, but you need to find healthy ways to vent that frustration rather than having fights).
There’s also a challenge for yourself to know that having MS doesn’t mean life is over. So although the hopes & desires you have for the future may not happen now, that’s not to say you can’t have any future - you just need to change what those hopes & desires are. There’s all kinds of things you can do. And that’s probably a key thing for any relationship to keep it healthy - being able to go & have experiences, both as individuals & as a couple, that will bring energy and life into the relationship.
That all felt like a bit of a ramble, but I hope at least some of it was useful! But like I say, it will be tough, but it can also be good, if you’re both willing to work it through.