I have enteropathic arthritis (side effect of crohn's disease) and have had a different experience that might be useful.
I was on methotrexate for years prior to having kids. I went through trying to get off it and stay off for 6 months again and again in order to safely have kids and every time I flared up right before I was clear of it (though the guidelines have now changed and it's 3 months clear assuming your folate levels have recovered, which can be checked by a blood test). I found the methotrexate extremely hard to be on (injections were better than the tablets though), particularly the nausea and the fatigue.
Eventually, for reasons unrelated, I changed consultant and my new one was a revelation. We changed my meds to Azathioprine (a very similar drug to mtx, older and theoretically with worse side effects, but i've experienced none), which you can get pregnant/breastfeed on and I combine it with Humira, which you can also have whilst pregnant/breastfeeding. When I had my first child it was still not recommended to get pregnant on humira (though not contraindicated like methotrexate), not because of any known risk, just that not enough people had been pregnant on it accidentally/through lack of other options to develop a database of outcomes to see if it was safe or not. They have since changed it's status and it's now recommended for people with autoimmune diseases that need to remain on meds.
Obviously not everyone wants to take strong medications while pregnant but being off meds was simply not an option for me - my autoimmune disease posed a far greater risk to a pregnancy/child than the drugs did. I have had two, healthy children whilst taking these drugs. My sons bloods were checked as a newborn and again when a few months old to make sure his immune system hadn't been affected by the immunosuppressants i was on and he was found to be in perfect health. Azathioprine passes in small amounts through breastmilk but not enough to have any effect on the child. Humira is destroyed by the digestive system so no concerns there. I breastfed my son til he was 2.5 and am still going with my nearly 2 year old daughter.
As I had c-sections I had to come off the humira just before and for 2 months after due to the infection risk from the surgery. With both children I restarted the humira 2 months after delivery and have managed to avoid a flare up both times. If you have a natural delivery you only need to come off the meds if you have significant tearing/stitches.
I appreciate not everyone wants to be on meds while pregnant/breastfeeding, but I just wanted to put another option out there for you. If you go onto meds that you can safely have children on, then you buy yourself time to talk to your husband/leave your options open with regards to more children.
Just as a final note, I was constantly having small flares, pain, exhaustion etc on methotrexate even when my disease was considered to be "well controlled". Going onto humira and azathrioprine was an absolute revelation; it's almost like I don't have this bloody disease. I feel so well! I play squash (well, pre kids I did, now I fit a game in once in a while!!) walk everywhere, have minimal pain and the fatigue is more from sleep refusing children than the disease and the meds. It's changed my life completely! After over a decade of pain and struggling I got my life back when I went on this combination of meds. I've been in remission for 6 years now and have a life I could only dream about in the years following diagnosis and on methotrexate. Obviously we all respond differently to the drugs, but please don't give up hope that you might get your disease properly under control when you find the right meds.
(I'm going away on holiday today so might not get back to this thread for a bit, but if you have any questions please ask and I'll reply when I get back).