I don't know if i'll be of any help but my experience tells me that you can help him a lot by just talking to him and telling him that you are only his love and that the past is just it...past. " In order to trully live you have to die to the past everyday... ", someone said that once. I trully agree... Another aproach to the problem ( kind of sneaky but what the hell in war and love everything is fair ) is to mention the Caos Theory

, if you hadn't had all those ex and the past experiences you wouldn't be living that love today because everything you do makes the difference in the next second... So you lived that way...but it's that that permits the love you have today because if you would change anything in your past you would be changing yourself, your living and your future ( now it's yours present )...think about the future...it's yet to be written and you and your boyfriend are the ones with the pen in your hands ( " pen " although most writers use PC's

). The past is gone and unless you develop a time machine ( if you do please notify me ) just forget it, you can't change it. Today you can change everything, tomorrow doesn't exist...write it down with your boyfriend...
By the way...Portugal would be a perfect spot for a honey moon

... All the best for you and your boyfriend.
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Trust me it's paradise...