I'm sorry to hear that, I'm pretty much same age as you and have lived in shared house for 3 years - last year was the worst as there was a communal bathroom for 5 of us and I was flaring bad, the amount of mornings I'd be sat outside the bathroom in tears waiting for it to become free and had had an accident in the meantime! (those housemates really didn't get it, they tried to begin with and then just got fed up and gave up) this year I've moved into a different house with an ensuite just in case I flare again.
As for the infliximab, are you just on infliximab? Combining it with something like methotrexate (thats the combination I'm on) can extend its effect and makes it harder for your body to build antibodies to it. The combination of infliximab and methotrexate, in my case anyway, has made the effects of infusions last for 6months - 3 years. Obviously drugs work differently for different people but something like that might be worth trying?