I just can't wrap my brain around my H doing that with his A. I don't understand how you tell your committed partner you love her, and then immediately go have sex with someone else and tell that person you love her.
Most likely answer, "He said "I love you" to get in her panties", it was a line, not a "feeling". Not always the right answer, but, affair or not, a pretty standard playbook since, well.. As long as I've been alive, that's for sure, and I suspect long before that. "Love" has little/nothing to do with the vast majority of affairs (actually, all, except my W's) that I know of IRL. It's "say what you need to say to keep them coming around for sex", and that thing is almost always/often "I love you".
Think of it this way. You can love more than one child, why can’t a WS love more than one person?
This is a good way to look at it too. Another is "he loved what she did for him" (again, most likely answer, "blowjobs").
I've used this analogy before because I've heard men refer to it this way and I extended it. Men often refer to AP's as "take out", as in "a take out meal". At the time, I thought; well, that kind of makes sense, it's convenient, fills you up, and gets you through to the next meal. Not great food, but hey, when your hungry, right? Now, this is NOT to excuse this behavior, not at all, but it's how I thought about it at the time. Anyway, this lovely analogy can be extended though, I love my wife's cooking and ALSO love the food at my local brewery. Love them equally? Not even close, if the brewery closed, I'd think "darn it", if my wife stopped cooking, I'd probably go on hunger strike and die. I love her food a LOT more than any take out, both because I like the taste better, but also, she cares about me, she's making that food for me, where the brewery is making it for anyone with 20 bucks. But I'd still tell you, if you asked me, "How's the food at that joint", "I love it" would be my answer.
Love is an extremely slippery and inaccurate term. It can mean anything from "loving a song" (if you never heard it again, you probably wouldn't even notice) to "loving a person" so much so that you'd literally jump in front of a bullet for them because the thought of being without them is worse than death. But both things there are defined by the word "love". That's why I never even really asked my wife about "loving him", IDGAF to be honest, she "loves" her new shoes that I got her for Christmas too. I care about what she DID, not what she claims (or does not claim) to have felt.
Love (as I think most of us would define it) is just not, in the vast majority of cases, even tangentially related to most affairs. Now, of course, people "think it is", but that's not what affairs are "for". They suck at providing anything that resembles what most of us would consider "love', and excel at providing what most of us would consider "good sex". We argue this point all the time, but, if you look at the results of many affairs, what actually happened? Did Jim and Jane fall in love and wind up in this whirlwind/Shakespearean romance? Sure, it happens, but it's not common (one person might THINK they are in that romance, of course). What's real common, however, in fact, so common that we all say "if they were alone, they had sex", is that Jane gave Jim a BJ in a car somewhere, or behind a dumpster while people took video. If anyone enters into an affair for "love", they are looking in the wrong place. Affairs excel at exactly one thing, providing sex with someone new while not ending your marriage. Full stop, that's the one tangible thing they are "good at". If that's not what you're after, you are looking in the wrong place (by having an A).