question about spouse status with I-485 application

My boyfriend and I will get married before he files I-140 and I-485. Right now, he is H1 status and I'm using my OPT. We were told by his lawyer that if his application gets denied, the date we file I-485 will be counted as the start date of my unlawful presence and I may be subject to 3-10 years bar. Therefore, she suggested I change to H4 or H1B before we file I-485.

Does anybody have such experience? Could you please give us some suggestions?

Thanks a lot