Captain Cake:
from spending time with her I naturally gained some and she always tried to make me keep up with her eating habits (and of course I often chose to have food to encourage her as well) and I found after gaining some that I actually really enjoyed it on myself too.
my experience was very similar - i have posted about it elsewhere in the forums, so i'll just summarize my experience: i was a fit, athletic feeder from my 20s and thru all of my 30s. it was when i started dating a ssbbw who was not interested in gaining that i kind of fell into it.
like @captain cake i found just being around her and her decadent eating & drinking habits had an effect on me. when we moved in together i was spending so much time with her that my gym time grew more and more infrequent. then it became a decision to "take some time off" from the gym, stop stressing about it, and just enjoy life.
the slippery slope was that some "time off" made it too hard to get back into going to the gym, and her influence on my appetites was too strong to resist! so even though we split up more than a year ago, i've continued to gain weight!
now my much slimmer girlfriend gets a kick out of feeding me sometimes.
which isn't helping me lose any weight, lol!