Hey there Rain Caster. Dealing with a partner and transition is definitely a challenging process. I am sure there are plenty of FtM folks on Eden who can suggest some good resources in terms of FtM specific stuff. I'm a non-transitioning MtF so I am not as knowledgeable in that realm of things.
My general advice on dealing with trans in a relationship (little background: I've been with my very accepting/supportive partner for 10+ years now)-
1. Go slowly, obviously if you feel the need to transition then you need to make it happen, but it will help your partner to make adjustments if you don't try and take it on all at once.
2. Communicate. A lot. Talk about your needs, your partner's feelings, and all the changes you will both go through.
3. Come out early and often. The more people you have that support you and your partner the better. It's harder to deal with difficulties if you have no real support network.
4. Sex and gender complicate relationships. Not every partner will be able/interested to stick through a relationship with a transitioning person, but the healthier your relationship in general the better chances you have.
5. Support your partner. Both so they can support you, and because it's the good partner thing to do.
6. Get professional support when you need it. Therapists can be really helpful for either/both of you.
Hope that's a little helpful.