i just beg anyone who wants to give advice to read the content first and then thinks twice before giving the advice because, who knows, if that would save a life.
Anyway, my dear there are lots of other things you can do for love so, don't let someone deceive you by saying having sex is his proof that you truly love him. let him see reason in your view that it's immoral to you as at now.
Mind you, also retrace your steps; probably you mis-behaved just of recent, if you notice anything that led him to doubting you now -after 3years- try to rectify such without any implication. BE WARNED! STDs are in town