Seriously, read a few threads on here, I'll share the stock phrases I've heard from men like this (my marriage broke down 5 years ago because some other woman fell for the same shit from my husband!) I shut down 3 married men in a week last summer - all with variations of what you're being told.
"I love her, but not like a husband should love a wife"
"I love her like a sister"
"I love her but I'm not in love with her"
"I care about her and I don't want to hurt her, but..."
"I'm never going to leave, the children are my priority, but I think I love you"
"she's not interested in spending time with me"
"It was an arranged marriage, we've agreed to stay together until the children leave home but there's no love"
"I don't love her, we're staying together for the children - we live almost entirely separate lives"
"She tricked me. I thought she was someone she wasn't and then, once we were married, she changed" (together 25 years, married 21, eldest child 15 - so plenty of time to leave if that were the truth)
I could go on but I don't really fancy regurgitating all the shit they've said about me - but generally attempts to flatter me by highlighting how different I am to their wives... - more confident; more adventurous; more interesting; more intelligent; more attractive; better figure; kinder; sweeter...
Full. Of. Shit.