Most serious LDS people have the goal of marrying in the temple, which to us is one of our most important goals because it unlocks a lot of blessings in the afterlife that wouldn't otherwise be possible. Most notably, the promise that your marriage and family bonds can continue beyond the grave.
To go to the temple, you need to be a member of the church in good standing. Like any faith, there are varying levels of commitment among members. Usually less than half of members are at the level of commitment for attending the temple, but a lot of those hope to be at that level someday. At my local church we have over 400 people on the membership rolls and about 160-180 attend each week, so there are a lot of people who are semi-committed, and even some who were baptized but haven't attended worship services in years.
If you're interested in marrying a Mormon without converting, those are the ones most likely to consider you a good prospect.
But I also regularly see people who appear to be serious members, and still marry a non-Mormon. I don't want to get your hopes up though. Anyone who takes our faith seriously will understand why the temple is a high priority, and would expect that a Mormon spouse would be hoping you'd convert someday, so they could be with you not just in this life, but in the next life also. I mean, what would you rather have, Lindsey Sterling for a couple decades in mortality, or Lindsey Sterling for a couple trillion years and beyond?
Yeah, Lindsey Sterling is awesome. What do you like best about her?