My boyfriend's mother has been trying to break us up or am I nuts?

I have been with my boyfriend for 4 years and he and I went to the romantic island of St. Martin with his parents. Well, this year his mother apparently invited him to go to St. Martin and she picked a month that I wouldn't be able to take the time off from work. He is going, but he told me that I cannot afford it. I told him that if he goes without me, I am done with him because it is such a selfish thing to do to your girlfriend knowing that we've been together for 4 years and he is just going to let his mother try to ruin this relationship. By the way this is not the first time she has invited him to go on trips when I couldn't take time off.
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There hasn't been any contact since our last talk. I am just trying to think things through and take all of your comments into consideration (even if I disagree). Any guys out there that may wannna comment?
My boyfriend's mother has been trying to break us up or am I nuts?
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