Well, Gaston and I have our Gaston collection...so if we ever broke up (or if Beast pushed him off of a roof), I suppose I would keep them all, as a memorial to his majesty and handsome-ness....
Just kidding.
But in all seriousness, I agree with others on this. Keep them separate for the most part. Maybe if you have some sort of bond over something, after you've been together for some time, collect that together. And in the event a breakup occurs, sell them all and split the money.
I don't think I could ever be with someone who doesn't collect at least ONE thing (I don't care if its seashells). I am a ridiculously obnoxious collector, and I really like dolls and pins. If I ever dated someone who didn't understand these things, I can't even see our relationship working out (I can just picture the fights over money and space!). I plan to have the basement of my house set aside for my collections, and to leave the rest of the home "normal" looking. If a significant other couldn't handle this, we just couldn't be together~ There is something to be understood about collectors, and most people can't understand us unless they collect something themselves.
My past boyfriends/partners have been critical of my collecting. I do spend a LOT of money on my things, but I never use anything but Paypal funds I've made from selling on the internet. I plan to keep it this way when I am older, so hopefully, I don't have to worry about fighting over me using all the savings on pins!! Lol.