I'm going to try and explain how canvassing works, in my party at least. Hopefully this will shed some light on whats going on with OP's leaflets...
So one thing that surprised me about canvassing is that the main aim is not necessarily to change peoples minds or convince them to support your party.
The main aim is to locate your supporters so that you can try to turn them out on election day. A secondary aim is to update your database for use in future elections.
You want to be able to track if your supporters have moved house or changed their alligence to another party or if supporters of other party's have come over to you. If you have good activists your database should improve over the years and become more useful to you.
So early in the campaign you will go out and do general canvassing. You want to knock as many doors as possible and find out what party, if any, the people support. You make a note of the answers and add it to a database.
Some people get a bit anxious to be door knocked and think we want to keep them talking on the doorstop for ages. We honestly dont. We just want to very quickly get some info and then move on.
Some people think it will cause awkwardness and hostility if they admit to supporting another party. Again no. We will just be happy to have that information to add to the database.
When the postal votes are issued you might then try and visit people who you think may vote for you and remind them to complete the postal vote.
Closer to the election you will then go around and knock the doors of people who have previously been identified as supporters and remind them of the election and check they still plan to vote.
At some point you might do an additional leaflet just for people you think might vote for you. You might also do a personal letter to party members or identified supporters. In the case of the OP who is getting stuff addressed to her DH: My guess is that he has given canvassers information at some point which has caused them to direct focused campaign materials at him.
In terms of OP's multiple leaflets: My guess is that the activists have attempted to canvass her a couple of times, found her out and on each occasion thought "oh well I'll just pop a leaflet through the door. That will be better than nothing"
I agree its not ideal to have multiple copies of the same one. We try to avoid that but it does happen sometimes.
If you want the minimum possible interaction with canvassers, my advice is to say the name of a party and then shut the door. If you say "Im busy right now" or "I haven't made up my mind" we will mark you as unknown and next time we are in your area your address will appear on the knock up sheets and we will knock your door again.
If you say the name of the party doing the canvassing- expect another visit to remind you to vote.
Dont do what some i know did and tell every party that you plan to vote for them "to get them go away". I does not get us to go away any faster and it guarantees you multiple follow up visits.
If you don't want to be bothered by canvassers- tell us explicitly and ask to be removed from the knock up sheets. If you get another visit: call up the candidates electoral agent and complain.
At the end of the day your vote is personal to you and its up to you whether you disclose your voting intentions.