My parents (with whom I have a strained relationship) have invited me, my husband and toddler ....?

Don't do it...if you already have a strained relationship with them... I can guarantee by the time you get back from your 8 days with them...you will be a wreck and the relationship will be destroyed beyond repair. Why would want to put yourself and family through this ?? I think it would be better to have the ( Heavy holiday burden ) and more....than spend 8 days totally stressed out of your mind...also it will not be fair on the little one.