There is truth in what you say, but "for every thing there is a time and place". If someone's affections towards their spouse are more aggressive, it is not often out of lust (as lust is desire without love, I do not believe spouses who love each other can lust after each other), but out of love, and so long as the affection is welcomed, it shouldn't be considered in any way not gentle just because the physical aspects are more vigorous, for the same gentle, caring love that brings a couple together manifests itself not by physical activity, but by a desire to fulfill your dearly beloved's every desire (including the kinky ones).
I feel that by defining what a couple can do between one another in the bedroom is to try and define love, and love takes many forms, some like a gentle butterfly, others like a raging inferno. Putting barriers on the unforbidden is only going to incite temptation; many people sin not because their actions are sinful, but because of the mentality behind them. Eating pork is not a sin, but in the old days it was, not because bacon is of the devil, but because of the rebellious mindset behind it.
As for "If you can't imagine Jesus doing something, it's probably not a good thing.", I can't honestly imagine Jesus having sex at all, since He did not take a wife.
It is ultimately a matter of semantics. What do
you feel comfortable doing with your partner? So long as it is based in love, is it not a kindness to fulfill your spouses wishes and prevent them from being tempted to seek fulfillment elsewhere? And so long as the gentle caring of the heart remains, the physical activity is only a manifestation of that feeling. Some people love their spouse so much that they can't restrain themselves to slow petting, but have to express the depth and strength of their passion more vigorously. Besides, Leviticus tells us not to mate with animals; if God puts down a rule which even the most depraved unbelievers know and agree with, then He's making certain to provide absolute clarity in His word so that even the simplest of fools can understand it. (Lucky for fools like me.)
God knows the heart of man and how he tries to justify his actions. It is why many Biblical passages are written so bluntly and repeated over and over; because God doesn't leave loopholes. He knows we're going to try and find a way around the rules. So he designed them so that the only way to get around them is to straight up deny or question their legitimacy, and by that point you're pretty much just telling God "I know better than you", and with that mentality you probably aren't actually seeking to do the right thing.
Sorry if I'm ranting.

I fully respect your opinion, and I understand that maybe God knows such behavior would not be good for you. I just have very strong feelings on the suppression of God-given sexual desires in the modern Christian church. So many doctrines of men. Ugh.

God wouldn't have made it so much fun if He didn't want us to enjoy it.