Me [30F] with my husband [30M] of 7 years; he lied to me about a trip he took with his mom (50s F) and tried to buy me off to make up for it.

Throwaway because I JUST got my husband into Dating.mobi so...you know.
TL;DR: I wanted to go to a bucket list location for Valentines Day and husband said we couldn't afford it. Accidentally found out he's there this weekend with his mom and he deliberately hid it from me and justified it by saying he was trying to surprise me with a gift from the city.
Background info (trying to keep is as short as possible, I'm sorry): I love my husband, we have a pretty strong relationship. I used to be really close to his mom and dad until the last two years or so. His sister is not only his best friend but also mine.
My distaste for his mother started when I found out that she had done some very disgusting, disturbing and predatory things to SIL throughout her lifetime. SIL put up a good front for the sake of my husband for a decade but once a straw broke the camel's back, she decided my husband was old enough to know the truth and she promptly went no contact with MIL.
My husband and FIL new a lot of the stuff that happened, but not all. My husband was overall distrustful of MIL but maintained a strained relationship because she's sick and he's afraid she'll die and he'll have regrets. FIL and MIL have been separated for twenty years; she lives with another man in another state but uses FIL for his insurance. FIL had a stroke not long after SIL went NC and though he recovered and is physically fine, he is a completely different person now and has made some very hurtful and abusive life choices regarding his children. He teamed up with his estranged wife to villainize SIL. We all cut contact with him after, but my husband still maintained a relationship with his mom despite everything.
We had a couple of arguments about his mom and ultimately decided that he can do whatever he wants in that category but that I will not have anything to do with his mother because of my principles. And, frankly, I think SIL needs some mother ****ing support right now. As a woman, a wife, sister, daughter, and HUMAN I just cannot condone the things she's done, regardless how sick MIL may or may not be at any given time (which is usually when it's most convenient for her).
Switching gears: Husband and I are currently doing long distance because of his job. It's temporary, we're pretty used to it and we make it work. For Valentines Day, I wanted to meet up with him in a city near his current location that I've been pining after for some time now. He talked me out of it because of money and we agreed it would be more cost effective for him to just come to me and we'd have a nice weekend in. No big deal. A week after our time together I relocated to our new town. He had told me his mom wanted to drive up to meet him the weekend of my road trip, and I asked him to put it off a week in case I needed some assistance or something. He agreed, all was fine.
Now to the problem at hand. I had totally forgotten that they had plans when I called him this afternoon. I hurried off the phone because I just don't want any part in any of it and I wanted to just leave them to it. I never asked where they were meeting or what they were doing for the same reason. An hour or so later, I clicked on our conversations and then on his contact info to track down an old picture I sent him. When I clicked on the info button, his current location was live. We had location sharing on during my drive so he could give my family updates and we just never turned it off. He was in the city I wanted to go to for Valentines Day...with the woman I despise the most in the world.
He's not a stupid man. He knows how I would feel about this and he never once bothered to mention it. I texted him and casually asked where they had decided to go for the weekend. He said somewhere north of the state capital, then I watched as his location went from "live" to "unavailable." I asked what town. He said they were near [insert other town nearby]. Then he tried changing the subject to small talk. I shut it down. I told him I knew exactly where he was and that I was hurt and confused by why he was being so shady.
He told me that he knew I'd be disappointed that I couldn't go so he thought he'd sneak in and out and get me something to make up for it. I told him I couldn't deal with this at the moment and that I'd talk to him Sunday. I honestly just don't want his disgusting mother to know we're in a fight and fill his head with whatever smut she comes up with.
I've asked myself all sorts of questions. Would I feel the same if he went with anyone else? No. Is that petty? Maybe. Idk. I also don't think he'd feel the need to be so sneaky or that he'd need to make anything up to me if he were there with anyone else. Do I feel like his heart was in the right place? Debatable. He knew he was doing something that would hurt me and chose to lie and sneak. Regardless if he didn't do this maliciously, he knew exactly how this would play out. If he didn't, then his empathy level is something to be concerned about.
Am I crazy? Am I overreacting? How do I approach this?
Edited for formatting.


Source.