How can my Catholic fiance and I (Lutheran) blend our religions in our marriage?

My boyfriend of nearly 3 years proposed to me last week. The wedding is a couple years away as we are both still in college. I come from a Lutheran family and he from a very Catholic one. At this point neither of us really wish to convert (and for him it would likely cause issues with his family, which I do not want to have happen). My family is fine with me becoming Catholic, but I'm not comfortable with everything in their religion. Finding a different religion is not something we wish to do either. I have also brought up alternating churches each week, but he's not very comfortable with that either. This has been the one sticking point in our relationship, but we both want to make this work and raise our children to know both religions. Does anyone have any suggestions for how we can make this work?