I think it can be common for teen boys to not want to do anything with/go anywhere with their mom - can be seen as babyish or uncool.
A lot of teen boys don't want to do anything with their family full stop.
It is also not unusual for teenagers to take you for granted am- especially if you are the one who us always there for them , in the background making sure they are safe, cared for, few etc.
They are craving the attention of their dad because it's not so readily available.
Your trip to Barcelona is definitely the right move. And you need to seriously consider what future, if any, you have with your DP as in 5 years time your youngest DS will be an adult.
But in all of this please make sure that your DC know that your love for them is unconditional; that if you and their father separate and they choose to live with him (although from what you've said I'm not sure this is what he would want) - that they know there will always be a home for them with you.
FWIW my teenage DS wouldn't want to be seen any where with me either even though I know he totally loves me for the mom who is the safe place for him.