I did this exact same thing almost 20 years ago to my ex. He was my first love and our break up was very traumatic on both sides.
I did it for a couple of reasons. For one, I just couldn't physically have them in my possession anymore. It pained me to do so and I didn't have anywhere to put them. I thought he was much stronger than me me emotionally, so I thought he could handle it.
Another reason I did it was to show that everything that he ever gave me, in the space of a 6 1/2 yr relationship, either purchased or made, could easily fit into a medium sized box. I realize that now, that it was a very petty thing to do, but I was still very angry and hurt at the time. He would easily spend money on friends for a round of drinks that cost $80.00 and I only received flowers once the entire time we were together and they were half-dead. I spoiled him constantly with gifts that were both bought ( and I wasn't rolling in it, believe me!) and handmade and although I know that you should give and not expect anything back, it is a little hard to accept when it feels like your boyfriend is spoiling everyone around him except you.
The last reason is because I felt, that even still through all the shit that we had been through that we would always love each other. Because of that, I felt that my love letters would be safe with him and that I would eventually get them back one day. I even mixed all of the love letters up to force him to put them back together. To get him to read it and realize that at one time we were good once. Silly, I know. Unfortunately, he never did send them back, so I misjudged that one.
Looking back, I wish I hadn't done it. It was all very young and dramatic, and now I don't have anything but my memories and one video and a couple of family photos to remind me that he even existed.
So, to answer your question, OP, I think she loved him a great deal. Although, I think the bigger question is why you are concerning yourself with an old flame? Unless she's actively pursuing him now, I wouldn't concern myself with it. Your husband has a right to his own private memories just like you do. If my DH had a box of things from his exes it wouldn't concern me. He had a life before me and I respect that, just as I would expect him to respect me having a past.