回复：他办亲属团聚绿卡，在他取得绿卡之前结婚，我可以加入他的申请

depending on which category of family based immigraiton. if he is 2B (unmarried son or daughter of lawful permanent resident), will lose priority and ineligible to get greencard for your boyfriend.if first preference, get married will cause dealy of his green card. there are also issues from Child Status Protection Act. need more specific info.