hun it is totally up to you. This is your baby...you make the decisions, NOT your MIL.
IMO it is unfair of them to be pressuring you to do anything.
It might be a decision for you & your Dh to make together...
but why does your DH think this is his decision any more than it is yours?

Have you asked him what made him have such a dramatic change of heart? Was it just what his mother had to say? It seems a bit unusual that he was so adamant that you continue, only to now be pressuring you to wean.

I would suggest having a look at some of the articles here on BB, also contact the ABA & see what they can send you. Back up your wish to continue BFing with literature stating the benefits to both you & bub. Maybe then he will be a bit more supportive?

ETA - I don't know if it will help any - but you could point out that in terms of convenience, BFing is portable, there's no washing up, it's always ready & at the right temp... there's a lot to be said for the convenience of BFing too!