K.
I'm not sure what to tell you - I'm trying to encourage my 19 month old son to wean by the beginning of March too (I'm due with baby #2 in June). You *can* certainly breastfeed while pregnant - it's completely safe. Lots of moms see their milk supply decrease but lots don't. I haven't had any change in mine yet. What works best for me is distraction with my son - he tends to want to nurse when he's bored or hungry. So frequently finding something fun for him to do or feeding him some real food will cause him to forget about asking. It's probably harder for you since you're at home all day. I'd try and see if you can drop one feeding every few weeks. Maybe some days you can get her to skip the morning meal, but other days she just can't seem to function without it. We manage to skip my son's evening nursing about 2/3 days, but if he's had an especially long/busy/good day and asks for it, I don't really have the heart to refuse him.
I talked to a friend about this and she said she basically went cold turkey with her kids (she's also a SAHM). Said that she had to pump a few times for the following weeks to keep herself comfortable, but then it was done. She said that some of her friends who weaned older children had so much trouble they actually had to leave the house for a weekend and when they returned, they just refused to nurse. That seemed to work ok too.
Mostly, it just depends on how much of a hard-a** you want to be about the whole thing, and how adamantly you want to quit.