My wife and her family are a good example of this. She cannot get into the top echelons of heaven without being sealed to a worthy priesthood holder in the temple for time and all eternity. A few weeks into the break, he moved to begin his EM residency. I would never convert. If you can't do that, realizing that your partner may never come around to your side of things, you are not ready to marry this person.
Somewhere down the road, you will find another girl who will be a much better match for you. There is no way she will may you without you going to the temple. Ultimately there are no guarantees but I'd say it's worth a shot. But daughter and I agreed that this teaching was unhealthy.
I read through a few of the LDS. How will this all be once we have children?. But that parent-child relationship was bound to change anyways as you become an adult. Trying to maintain a long-distance relationship with someone at home or attempting to date someone you meet while on mission are both distractions. Plan on her family trying to torpedo your relationship if you don't convert.
I often contemplate divorcing my husband so that I could seek happiness elsewhere, or at least companionship. We are both extremely busy, and maybe that's why we work, but we try to make the time for our relationship. Be open to the wisdom the Spirit will share. I say to you, decisions determine destiny. Thanks for pointing this stuff out.