I met my husband online and 6 months later we were engaged after a 12 day trip to Spain (we stayed with his sister.) That being said, we did not get married until 3 years later and me visiting him about every 6 months for 2-3 weeks each time. When we married, I stayed for a month. I suppose every couple works differently, but back when we were first engaged, him immigrating to the US was a consideration, but not a serious one. We knew we had a lot of learning and growing to do as a couple first. Now we've been married for 3 years in July, I lived with him for 18 months in his country and we have a much better idea of how we function as a couple. I just filed the I-130 in April. IMO, time together as a couple is important before making the choice to jump into the immigration process.