DS is aged 3.9yrs and since August we have sometimes noticed his behaviour deteriorates when he needs to share our attention with others and we wonder if this is jealousy and the best way of handling it.
In August we went on holiday for a week with SIL, BIL & DNephew(2). We had separate hotel rooms with them but when we spent time with them DS would often descend into tantrums (on the floor, crying) over the slightest thing; he'd always decide he wanted to do the opposite to what we had decided to do, so yet another tantrum and/or stroppy, rude behaviour. It became almost constant hysterics over nearly everything, and he ended up spoiling most of the holiday.
Since then I have taken him out with two different friends and their child, and very similar behaviour has followed: wants to do the opposite of what is planned, very stroppy and frequently ends up on the floor howling. We usually stop for a coffee and he becomes exceedingly irritating and badly behaved - sliding all over the chair, on the floor, knocking food and drinks over due to being deliberately careless, being rude and stroppy in conversation, throwing his toy car, tries to run off around the café etc. Due to this, it effectively means I can't really hold a conversation with friends at all. As soon as we part ways with friends he's completely calm and fine again.
However, this is not what he is like usually at all with us- as he's got older he's calmed down a lot etc and the only thing we can think of is that he doesn't like it that our (DF & I) attention is being shared with others. But then again, there are some family friends, and family, that this poor behaviour does not occur with.
Any thoughts? No siblings, doing very well at nursery and no behaviour issues there anymore (he did have some when he first started).