We've been together for roughly a year (next week is our one year anniversary). There's a rather odd and complicated story behind how we met and how we came to be where we are now, but I'll try to shorten it (the details are kind of important).
We knew each other for several years before becoming a couple, but were only really close until six months before the relationship started. Because we're a little over 5 years apart, we kept the relationship a secret for four months. I was 18, and he was 23. While my family and friends fully embraced the relationship, his family was a bit more skeptical. While I was in my first year of college when we met, I had been taking a semester off to work full time, save up money and transfer to a school on the west coast. We lived on opposite sides of the country and the relationship was long distance for the first six months (we visited each other every other month and video chatted in between).
We moved in during late spring. We've been a couple for a year now, and we've been living together for six months. I currently work full time and go to school part time in the evenings, and he's already working his dream job (and has been for over two years). We're well off, very comfortable, and we own a house so money is not a problem.
For those of you who will say we moved in too soon, we did keep to separate bedrooms until recently, to avoid moving "too fast".
The main issue is that everyone approves whole heartedly of the relationship, except for his parents. His mom seems happier about it than his dad and usually refrains from commenting, but his dad has been very vocal with his opinion. His dad thought we moved in too fast, that I was too young (even though I've been living on my own for almost two years now), and that we haven't been together long enough to consider the relationship serious. In his dad's mind, because we kept it a secret for four months, we've only been together for eight months instead of a year (is there really a difference?). I can understand why his dad's a little skeptical.
We intend to get married--not until late 2012--but we do intend to. In fact, we've started taking the premarital course at a local church. He's going to propose sometime this winter to make it a little more "official", but we're heading in that direction with or without the pretty accessory. Right now we're focused on improving ourselves as individuals and strengthening our relationship to prepare for marriage in the future (it's a big step, after all).
He spoke to his dad a couple months back about the concept of proposing, but his dad was very against the idea. His dad thinks that one should not even consider marrying a person (should put it off the table) for two years.
By the time any wedding happens, we'll have been together for three years. A long engagement is hardly dangerous (especially since we've been taking a premarital course and will start counseling in the spring). However, it seems that his dad has trouble understanding that. To him, engagement = getting married within six months. That's hardly the case.
Getting engaged and telling him after the fact would offend him greatly, so the boyfriend is trying to find a way to explain it to him beforehand so that he has more time to digest and accept it. It's just really hard to think of the best way to do it, since we're limited to IM, email and phone calls with his parents.
What I'm asking is: what's the best, most respectful way to explain this to his father?